Migrate data paths to ~/.local/share/fluorine/, add native build, fix %command% and system Proton scanning

- All data paths migrated from ~/.var/app/com.fluorine.manager/ to
  ~/.local/share/fluorine/ so native and Flatpak builds share the same
  instances, plugins, and configs
- New fluorinepaths.h/.cpp with fluorineDataDir() helper and one-time
  migration from old path (writes MOVED.txt breadcrumb)
- New libs/nak/src/paths.rs as Rust equivalent (data_dir())
- Strip %command% tokens from launch wrapper in protonlauncher.cpp
- Always scan /usr/share/steam/compatibilitytools.d/ for system Proton
  packages (Arch installs Proton there); add Flatpak filesystem permission
- Native build (build-native.sh) installs to ~/.local/share/fluorine/
  with desktop entry and ~/.local/bin symlink instead of portable zip
- build-flatpak.sh wrapper for Flatpak builds
- Fix container locale (LANG=C.UTF-8) for AutoUic warnings
- Fix prefixExists() to handle both compatdata and pfx directory layouts
- Fix globalInstancesRootPath() to use fluorineDataDir() on Linux
- Fix umu-run Flatpak lookup to use fluorineDataDir()
- Update README with build instructions and Arch dependency list

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

37 files changed, 129 insertions, 78 deletions

diff --git a/libs/7zip/CMakeLists.txt b/libs/7zip/CMakeLists.txt
index 915be26..5db6f0a 100644
--- a/libs/7zip/CMakeLists.txt
+++ b/libs/7zip/CMakeLists.txt
@@ -443,7 +443,7 @@ target_compile_options(7z PRIVATE
   -Wno-unused-parameter
   -Wno-sign-compare
   -Wno-missing-field-initializers
-  -Wno-reorder
+  $<$<COMPILE_LANGUAGE:CXX>:-Wno-reorder>
 )
 
 target_link_libraries(7z PRIVATE pthread dl)
diff --git a/libs/basic_games/basic_game.py b/libs/basic_games/basic_game.py
index b3ff73d..1047bbf 100644
--- a/libs/basic_games/basic_game.py
+++ b/libs/basic_games/basic_game.py
@@ -31,11 +31,11 @@ def _find_wine_userprofile() -> str | None:
 
     candidates: list[str] = []
 
-    # 1. Flatpak data prefix (most common for Fluorine)
-    flatpak_pfx = os.path.expanduser(
-        "~/.var/app/com.fluorine.manager/Prefix/pfx"
+    # 1. Fluorine data prefix (shared by native and Flatpak builds)
+    fluorine_pfx = os.path.expanduser(
+        "~/.local/share/fluorine/Prefix/pfx"
     )
-    candidates.append(flatpak_pfx)
+    candidates.append(fluorine_pfx)
 
     # 2. Fluorine config prefix_path
     try:
diff --git a/libs/bsa_ffi/src/archive/mod.rs b/libs/bsa_ffi/src/archive/mod.rs
index 247789e..27b1db1 100644
--- a/libs/bsa_ffi/src/archive/mod.rs
+++ b/libs/bsa_ffi/src/archive/mod.rs
@@ -201,6 +201,7 @@ pub enum GameVersion {
     StarfieldV3,
 }
 
+#[allow(dead_code)]
 impl GameVersion {
     /// Get display name for this game version
     pub fn display_name(&self) -> &'static str {
@@ -353,6 +354,7 @@ impl GameVersion {
 }
 
 /// Detect game version from archive format
+#[allow(dead_code)]
 pub fn detect_game_version(archive_path: &Path) -> Option<GameVersion> {
     match detect_format(archive_path) {
         Some(ArchiveFormat::Tes3Bsa) => Some(GameVersion::Morrowind),
diff --git a/libs/bsapacker/src/qlibbsarch/QLibbsarch.h b/libs/bsapacker/src/qlibbsarch/QLibbsarch.h
index 7af53f4..9e37e05 100644
--- a/libs/bsapacker/src/qlibbsarch/QLibbsarch.h
+++ b/libs/bsapacker/src/qlibbsarch/QLibbsarch.h
@@ -3,6 +3,7 @@
 #include <libbsarch/libbsarch.h>
 #include <string>
 #include <stdexcept>
+#include <cstring>
 #include <QDebug>
 #include <QDir>
 #include <QStringList>
@@ -23,7 +24,9 @@ namespace QLibBsarch
 	{
 		if (result.code == BSA_RESULT_EXCEPTION)
 		{
-			const std::string &error = QLibBsarch::wcharToString(result.text);
+			wchar_t aligned_text[1024];
+			std::memcpy(aligned_text, result.text, sizeof(aligned_text));
+			const std::string error = QLibBsarch::wcharToString(aligned_text);
 			LOG_LIBBSARCH << QString::fromStdString(error);
 			throw std::runtime_error(error);
 		}
@@ -31,12 +34,7 @@ namespace QLibBsarch
 
 	inline void checkResult(const bsa_result_message_buffer_s &result)
 	{
-		if (result.message.code == BSA_RESULT_EXCEPTION)
-		{
-			const std::string &error = QLibBsarch::wcharToString(result.message.text);
-			LOG_LIBBSARCH << QString::fromStdString(error);
-			throw std::runtime_error(error);
-		}
+		checkResult(result.message);
 	}
 
 } // namespace QLibBsarch
diff --git a/libs/bsatk/src/CMakeLists.txt b/libs/bsatk/src/CMakeLists.txt
index 99a0f26..d9b7be1 100644
--- a/libs/bsatk/src/CMakeLists.txt
+++ b/libs/bsatk/src/CMakeLists.txt
@@ -1,4 +1,7 @@
 cmake_minimum_required(VERSION 3.16)
+if(POLICY CMP0167)
+  cmake_policy(SET CMP0167 NEW)
+endif()
 
 find_package(Boost REQUIRED COMPONENTS thread)
 find_package(ZLIB REQUIRED)
diff --git a/libs/bsatk/src/bsaarchive.cpp b/libs/bsatk/src/bsaarchive.cpp
index e1655c1..4ae94a6 100644
--- a/libs/bsatk/src/bsaarchive.cpp
+++ b/libs/bsatk/src/bsaarchive.cpp
@@ -446,11 +446,9 @@ EErrorCode Archive::write(const char* fileName)
     writeHeader(outfile, determineFileFlags(fileNames),
                 static_cast<BSAULong>(folderNames.size()), folderNamesLength,
                 fileNamesLength);
-#pragma message("folders (and files?) need to be sorted by hash!")
     // dummy-pass: before we can store the actual folder data
 
     // prepare folder and file headers
-#pragma message("it's unnecessary to write actual data, placeholders are sufficient")
     for (std::vector<Folder::Ptr>::const_iterator folderIter = folders.begin();
          folderIter != folders.end(); ++folderIter) {
       (*folderIter)->writeHeader(outfile);
@@ -673,7 +671,6 @@ EErrorCode Archive::extractDirect(File::Ptr file, std::ofstream& outFile) const
     if (namePrefixed()) {
       std::string fullName = readBString(m_File);
       if (size <= fullName.length()) {
-#pragma message("report error!")
         return result;
       }
       size -= fullName.length() + 1;
@@ -735,7 +732,6 @@ std::shared_ptr<unsigned char[]> Archive::decompress(unsigned char* inBuffer,
       stream.next_out  = reinterpret_cast<Bytef*>(outBuffer.get());
       zlibRet          = inflate(&stream, Z_NO_FLUSH);
       if ((zlibRet != Z_OK) && (zlibRet != Z_STREAM_END) && (zlibRet != Z_BUF_ERROR)) {
-#pragma message("pass result code to caller")
         throw std::runtime_error("invalid data");
       }
     } while (stream.avail_out == 0);
@@ -824,7 +820,6 @@ EErrorCode Archive::extractCompressed(File::Ptr file, std::ofstream& outFile) co
     if (namePrefixed()) {
       std::string fullName = readBString(m_File);
       if (inSize <= fullName.length()) {
-#pragma message("report error!")
         return result;
       }
       inSize -= fullName.length() + 1;
@@ -850,7 +845,6 @@ EErrorCode Archive::extractCompressed(File::Ptr file, std::ofstream& outFile) co
     if (namePrefixed()) {
       std::string fullName = readBString(m_File);
       if (inSize <= fullName.length()) {
-#pragma message("report error!")
         return result;
       }
       inSize -= fullName.length() + 1;
@@ -907,7 +901,6 @@ void Archive::readFiles(std::queue<FileInfo>& queue, boost::mutex& mutex,
       if (namePrefixed()) {
         std::string fullName = readBString(m_File);
         if (size <= fullName.length()) {
-#pragma message("report error!")
           continue;
         }
         size -= fullName.length() + 1;
@@ -954,7 +947,6 @@ void Archive::readFiles(std::queue<FileInfo>& queue, boost::mutex& mutex,
                        reinterpret_cast<char*>(unpackedChunk.get()), length);
                 unpackedChunk.reset();
               } catch (const std::exception&) {
-#pragma message("report error!")
                 continue;
               }
             } else {
@@ -1029,7 +1021,6 @@ void Archive::extractFiles(const std::string& targetDirectory,
                              fstream::out | fstream::binary | fstream::trunc);
 
     if (!outputFile.is_open()) {
-#pragma message("report error!")
       continue;
       // return ERROR_ACCESSFAILED;
     }
@@ -1052,7 +1043,6 @@ void Archive::extractFiles(const std::string& targetDirectory,
               buffer.reset();
             }
           } catch (const std::exception&) {
-#pragma message("report error!")
             dataBuffer.first.reset();
             fileInfo.data.first.reset();
             continue;
@@ -1121,7 +1111,6 @@ void Archive::extractFiles(const std::string& targetDirectory,
                            dataBuffer.second);
         }
       } catch (const std::exception&) {
-#pragma message("report error!")
         dataBuffer.first.reset();
         fileInfo.data.first.reset();
         continue;
@@ -1151,7 +1140,6 @@ EErrorCode Archive::extractAll(
     const std::function<bool(int value, std::string fileName)>& progress,
     bool overwrite)
 {
-#pragma message("report errors")
   createFolders(outputDirectory, m_RootFolder);
 
   std::vector<File::Ptr> fileList;
diff --git a/libs/bsatk/src/bsafile.cpp b/libs/bsatk/src/bsafile.cpp
index db4e4e6..3179c63 100644
--- a/libs/bsatk/src/bsafile.cpp
+++ b/libs/bsatk/src/bsafile.cpp
@@ -104,7 +104,6 @@ EErrorCode File::writeData(fstream& sourceArchive, fstream& targetArchive) const
 
   if (m_SourceFile.length() == 0) {
     // copy from source archive
-#pragma message("we may have to compress/decompress!")
     sourceArchive.seekg(m_DataOffset, fstream::beg);
 
     try {
diff --git a/libs/game_bethesda/src/gamebryo/dummybsa.cpp b/libs/game_bethesda/src/gamebryo/dummybsa.cpp
index 7b0f877..3fbd2ef 100644
--- a/libs/game_bethesda/src/gamebryo/dummybsa.cpp
+++ b/libs/game_bethesda/src/gamebryo/dummybsa.cpp
@@ -19,6 +19,7 @@ along with Mod Organizer.  If not, see <http://www.gnu.org/licenses/>.
 
 #include "dummybsa.h"
 #include <QFile>
+#include <stdexcept>
 #ifdef _WIN32
 #define WIN32_LEAN_AND_MEAN
 #include <Windows.h>
@@ -184,7 +185,10 @@ void DummyBSA::writeFileRecordBlocks(QFile& file, const std::string& folderName)
 void DummyBSA::write(const QString& fileName)
 {
   QFile file(fileName);
-  file.open(QIODevice::WriteOnly);
+  if (!file.open(QIODevice::WriteOnly)) {
+    throw std::runtime_error(
+        QString("failed to open dummy BSA for writing: %1").arg(fileName).toStdString());
+  }
 
   m_TotalFileNameLength = static_cast<unsigned long>(m_FileName.length() + 1);
 
diff --git a/libs/game_bethesda/src/gamebryo/gamebryosavegame.cpp b/libs/game_bethesda/src/gamebryo/gamebryosavegame.cpp
index 523df0d..7625af3 100644
--- a/libs/game_bethesda/src/gamebryo/gamebryosavegame.cpp
+++ b/libs/game_bethesda/src/gamebryo/gamebryosavegame.cpp
@@ -9,6 +9,7 @@
 #include <QFileInfo>
 #include <QScopedArrayPointer>
 #include <QTime>
+#include <QTimeZone>
 
 #ifdef _WIN32
 #include <Windows.h>
@@ -90,7 +91,7 @@ void GamebryoSaveGame::setCreationTime(_SYSTEMTIME const& ctime)
   QTime time;
   time.setHMS(ctime.wHour, ctime.wMinute, ctime.wSecond, ctime.wMilliseconds);
 
-  m_CreationTime = QDateTime(date, time, Qt::UTC);
+  m_CreationTime = QDateTime(date, time, QTimeZone::UTC);
 }
 
 GamebryoSaveGame::FileWrapper::FileWrapper(QString const& filepath,
diff --git a/libs/game_bethesda/src/gamebryo/gamegamebryo.cpp b/libs/game_bethesda/src/gamebryo/gamegamebryo.cpp
index caeeed0..1bcc2c0 100644
--- a/libs/game_bethesda/src/gamebryo/gamegamebryo.cpp
+++ b/libs/game_bethesda/src/gamebryo/gamegamebryo.cpp
@@ -495,7 +495,11 @@ void GameGamebryo::copyToProfile(QString const& sourcePath,
     sourceFile = resolveFileCaseInsensitive(sourceFile);
     if (!MOBase::shellCopy(sourceFile, filePath)) {
       // if copy file fails, create the file empty
-      QFile(filePath).open(QIODevice::WriteOnly);
+      QFile outputFile(filePath);
+      if (!outputFile.open(QIODevice::WriteOnly)) {
+        MOBase::log::warn("Failed to create fallback file '{}': {}", filePath,
+                          outputFile.errorString());
+      }
     }
   }
 }
diff --git a/libs/game_bethesda/src/games/enderal/enderalsavegame.cpp b/libs/game_bethesda/src/games/enderal/enderalsavegame.cpp
index cd9beb3..235bf1c 100644
--- a/libs/game_bethesda/src/games/enderal/enderalsavegame.cpp
+++ b/libs/game_bethesda/src/games/enderal/enderalsavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 using SYSTEMTIME = _SYSTEMTIME;
 
@@ -14,7 +15,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/enderalse/enderalsesavegame.cpp b/libs/game_bethesda/src/games/enderalse/enderalsesavegame.cpp
index 2662505..365ca37 100644
--- a/libs/game_bethesda/src/games/enderalse/enderalsesavegame.cpp
+++ b/libs/game_bethesda/src/games/enderalse/enderalsesavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 union _ULARGE_INTEGER {
   struct {
@@ -22,7 +23,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/fallout4/fallout4savegame.cpp b/libs/game_bethesda/src/games/fallout4/fallout4savegame.cpp
index 2f88d1b..17863ad 100644
--- a/libs/game_bethesda/src/games/fallout4/fallout4savegame.cpp
+++ b/libs/game_bethesda/src/games/fallout4/fallout4savegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 using SYSTEMTIME = _SYSTEMTIME;
 
@@ -14,7 +15,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/fallout4london/fo4londonsavegame.cpp b/libs/game_bethesda/src/games/fallout4london/fo4londonsavegame.cpp
index ead2d1a..c87d107 100644
--- a/libs/game_bethesda/src/games/fallout4london/fo4londonsavegame.cpp
+++ b/libs/game_bethesda/src/games/fallout4london/fo4londonsavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 using SYSTEMTIME = _SYSTEMTIME;
 
@@ -14,7 +15,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/fallout4vr/fallout4vrsavegame.cpp b/libs/game_bethesda/src/games/fallout4vr/fallout4vrsavegame.cpp
index cf29aae..d29c4fa 100644
--- a/libs/game_bethesda/src/games/fallout4vr/fallout4vrsavegame.cpp
+++ b/libs/game_bethesda/src/games/fallout4vr/fallout4vrsavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 using SYSTEMTIME = _SYSTEMTIME;
 
@@ -14,7 +15,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/fallout76/fallout76savegame.cpp b/libs/game_bethesda/src/games/fallout76/fallout76savegame.cpp
index 66e8a00..c070429 100644
--- a/libs/game_bethesda/src/games/fallout76/fallout76savegame.cpp
+++ b/libs/game_bethesda/src/games/fallout76/fallout76savegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 using SYSTEMTIME = _SYSTEMTIME;
 
@@ -14,7 +15,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/skyrim/skyrimsavegame.cpp b/libs/game_bethesda/src/games/skyrim/skyrimsavegame.cpp
index bd16036..621692e 100644
--- a/libs/game_bethesda/src/games/skyrim/skyrimsavegame.cpp
+++ b/libs/game_bethesda/src/games/skyrim/skyrimsavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 // SYSTEMTIME is _SYSTEMTIME (defined in gamebryosavegame.h for Linux)
 using SYSTEMTIME = _SYSTEMTIME;
@@ -16,7 +17,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;  // leftover 100ns units
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d = dt.date();
   const QTime t = dt.time();
 
diff --git a/libs/game_bethesda/src/games/skyrimse/skyrimsesavegame.cpp b/libs/game_bethesda/src/games/skyrimse/skyrimsesavegame.cpp
index d68ba19..59b9b6e 100644
--- a/libs/game_bethesda/src/games/skyrimse/skyrimsesavegame.cpp
+++ b/libs/game_bethesda/src/games/skyrimse/skyrimsesavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 // Windows ULARGE_INTEGER union for 64-bit FILETIME math
 union _ULARGE_INTEGER {
@@ -29,7 +30,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   int64_t unixSecs = static_cast<int64_t>(ull.QuadPart / 10000000ULL) - 11644473600LL;
   uint64_t remainderHns = ull.QuadPart % 10000000ULL;  // leftover 100ns units
 
-  QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   QDate d      = dt.date();
   QTime t      = dt.time();
 
diff --git a/libs/game_bethesda/src/games/skyrimvr/skyrimvrsavegame.cpp b/libs/game_bethesda/src/games/skyrimvr/skyrimvrsavegame.cpp
index 1670dc8..75b3683 100644
--- a/libs/game_bethesda/src/games/skyrimvr/skyrimvrsavegame.cpp
+++ b/libs/game_bethesda/src/games/skyrimvr/skyrimvrsavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 // Windows ULARGE_INTEGER union for 64-bit FILETIME math
 union _ULARGE_INTEGER {
@@ -25,7 +26,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;  // leftover 100ns units
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d = dt.date();
   const QTime t = dt.time();
 
diff --git a/libs/game_bethesda/src/games/starfield/starfieldsavegame.cpp b/libs/game_bethesda/src/games/starfield/starfieldsavegame.cpp
index 49653cb..9640b75 100644
--- a/libs/game_bethesda/src/games/starfield/starfieldsavegame.cpp
+++ b/libs/game_bethesda/src/games/starfield/starfieldsavegame.cpp
@@ -4,6 +4,7 @@
 #include <Windows.h>
 #else
 #include <QDateTime>
+#include <QTimeZone>
 
 using SYSTEMTIME = _SYSTEMTIME;
 
@@ -14,7 +15,7 @@ static void FileTimeToSystemTime(const FILETIME* ft, SYSTEMTIME* st)
   const int64_t unixSecs = static_cast<int64_t>(ticks / 10000000ULL) - 11644473600LL;
   const uint64_t remainderHns = ticks % 10000000ULL;
 
-  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, Qt::UTC);
+  const QDateTime dt = QDateTime::fromSecsSinceEpoch(unixSecs, QTimeZone::UTC);
   const QDate d      = dt.date();
   const QTime t      = dt.time();
 
diff --git a/libs/installer_fomod/src/fomodinstallerdialog.cpp b/libs/installer_fomod/src/fomodinstallerdialog.cpp
index 0fa6bfc..f675e3d 100644
--- a/libs/installer_fomod/src/fomodinstallerdialog.cpp
+++ b/libs/installer_fomod/src/fomodinstallerdialog.cpp
@@ -127,11 +127,15 @@ int FomodInstallerDialog::bomOffset(const QByteArray& buffer)
   static const unsigned char BOM_UTF8[]    = {0xEF, 0xBB, 0xBF};
   static const unsigned char BOM_UTF16BE[] = {0xFE, 0xFF};
   static const unsigned char BOM_UTF16LE[] = {0xFF, 0xFE};
+  auto startsWithBytes = [&buffer](const unsigned char* bytes, qsizetype size) {
+    return buffer.startsWith(
+        QByteArrayView(reinterpret_cast<const char*>(bytes), size));
+  };
 
-  if (buffer.startsWith(reinterpret_cast<const char*>(BOM_UTF8)))
+  if (startsWithBytes(BOM_UTF8, sizeof(BOM_UTF8)))
     return 3;
-  if (buffer.startsWith(reinterpret_cast<const char*>(BOM_UTF16BE)) ||
-      buffer.startsWith(reinterpret_cast<const char*>(BOM_UTF16LE)))
+  if (startsWithBytes(BOM_UTF16BE, sizeof(BOM_UTF16BE)) ||
+      startsWithBytes(BOM_UTF16LE, sizeof(BOM_UTF16LE)))
     return 2;
 
   return 0;
@@ -150,25 +154,30 @@ QByteArray skipXmlHeader(QIODevice& file)
   static const unsigned char UTF16LE[]     = {0x3C, 0x00, 0x3F, 0x00};
   static const unsigned char UTF16BE[]     = {0x00, 0x3C, 0x00, 0x3F};
   static const unsigned char UTF8[]        = {0x3C, 0x3F, 0x78, 0x6D};
+  auto startsWithBytes = [](const QByteArray& bytes, const unsigned char* prefix,
+                            qsizetype size) {
+    return bytes.startsWith(
+        QByteArrayView(reinterpret_cast<const char*>(prefix), size));
+  };
 
   file.seek(0);
   QByteArray rawBytes = file.read(4);
   QTextStream stream(&file);
   int bom = 0;
-  if (rawBytes.startsWith((const char*)UTF16LE_BOM)) {
+  if (startsWithBytes(rawBytes, UTF16LE_BOM, sizeof(UTF16LE_BOM))) {
     stream.setEncoding(QStringConverter::Encoding::Utf16LE);
     bom = 2;
-  } else if (rawBytes.startsWith((const char*)UTF16BE_BOM)) {
+  } else if (startsWithBytes(rawBytes, UTF16BE_BOM, sizeof(UTF16BE_BOM))) {
     stream.setEncoding(QStringConverter::Encoding::Utf16BE);
     bom = 2;
-  } else if (rawBytes.startsWith((const char*)UTF8_BOM)) {
+  } else if (startsWithBytes(rawBytes, UTF8_BOM, sizeof(UTF8_BOM))) {
     stream.setEncoding(QStringConverter::Encoding::Utf8);
     bom = 3;
-  } else if (rawBytes.startsWith(QByteArray((const char*)UTF16LE, 4))) {
+  } else if (startsWithBytes(rawBytes, UTF16LE, sizeof(UTF16LE))) {
     stream.setEncoding(QStringConverter::Encoding::Utf16LE);
-  } else if (rawBytes.startsWith(QByteArray((const char*)UTF16BE, 4))) {
+  } else if (startsWithBytes(rawBytes, UTF16BE, sizeof(UTF16BE))) {
     stream.setEncoding(QStringConverter::Encoding::Utf16BE);
-  } else if (rawBytes.startsWith(QByteArray((const char*)UTF8, 4))) {
+  } else if (startsWithBytes(rawBytes, UTF8, sizeof(UTF8))) {
     stream.setEncoding(QStringConverter::Encoding::Utf8);
   }  // otherwise maybe the textstream knows the encoding?
 
diff --git a/libs/installer_fomod_plus/installer/CMakeLists.txt b/libs/installer_fomod_plus/installer/CMakeLists.txt
index 70018ff..07a670b 100644
--- a/libs/installer_fomod_plus/installer/CMakeLists.txt
+++ b/libs/installer_fomod_plus/installer/CMakeLists.txt
@@ -29,7 +29,7 @@ FetchContent_Declare(
                 -P ${CMAKE_CURRENT_LIST_DIR}/../cmake/patch_pugixml.cmake
 )
 
-FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz)
+FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
 FetchContent_MakeAvailable(pugixml json)
 
 set(project_type plugin)
diff --git a/libs/installer_fomod_plus/patchwizard/CMakeLists.txt b/libs/installer_fomod_plus/patchwizard/CMakeLists.txt
index be46b32..2cb8ebb 100644
--- a/libs/installer_fomod_plus/patchwizard/CMakeLists.txt
+++ b/libs/installer_fomod_plus/patchwizard/CMakeLists.txt
@@ -14,7 +14,7 @@ file(GLOB SHARE_SOURCES "${CMAKE_CURRENT_SOURCE_DIR}/../share/**/*.cpp")
 
 add_library(fomod_plus_patch_wizard SHARED ${PATCHWIZARD_SOURCES} ${SHARE_SOURCES})
 
-FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz)
+FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
 FetchContent_Declare(pugixml GIT_REPOSITORY https://github.com/zeux/pugixml GIT_TAG v1.14)
 FetchContent_MakeAvailable(pugixml json)
 
diff --git a/libs/installer_fomod_plus/scanner/CMakeLists.txt b/libs/installer_fomod_plus/scanner/CMakeLists.txt
index daea477..f50dea2 100644
--- a/libs/installer_fomod_plus/scanner/CMakeLists.txt
+++ b/libs/installer_fomod_plus/scanner/CMakeLists.txt
@@ -13,7 +13,7 @@ file(GLOB_RECURSE SCANNER_SOURCES CONFIGURE_DEPENDS
 
 add_library(fomod_plus_scanner SHARED ${SCANNER_SOURCES})
 
-FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz)
+FetchContent_Declare(json URL https://github.com/nlohmann/json/releases/download/v3.11.3/json.tar.xz DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
 FetchContent_Declare(pugixml GIT_REPOSITORY https://github.com/zeux/pugixml GIT_TAG v1.14)
 FetchContent_MakeAvailable(pugixml json)
 
diff --git a/libs/nak/src/deps/tools.rs b/libs/nak/src/deps/tools.rs
index c97247c..0e3e356 100644
--- a/libs/nak/src/deps/tools.rs
+++ b/libs/nak/src/deps/tools.rs
@@ -1,7 +1,7 @@
 //! Linux tool management (winetricks, cabextract)
 //!
 //! Handles downloading and managing Linux CLI tools.
-//! Tools are stored in ~/.var/app/com.fluorine.manager/bin/ for Fluorine Manager.
+//! Tools are stored in ~/.local/share/fluorine/bin/ for Fluorine Manager.
 
 use std::error::Error;
 use std::fs;
@@ -13,14 +13,13 @@ use std::process::Command;
 use crate::logging::{log_error, log_info, log_warning};
 
 // ============================================================================
-// NaK Bin Directory (~/.var/app/com.fluorine.manager/bin/)
+// NaK Bin Directory (~/.local/share/fluorine/bin/)
 // ============================================================================
 
-/// Get the tool bin directory path (~/.var/app/com.fluorine.manager/bin/)
+/// Get the tool bin directory path (~/.local/share/fluorine/bin/)
 /// This is accessible from both native and Flatpak environments.
 pub fn get_nak_bin_path() -> PathBuf {
-    let home = std::env::var("HOME").unwrap_or_else(|_| "/tmp".to_string());
-    PathBuf::from(home).join(".var/app/com.fluorine.manager/bin")
+    crate::paths::data_dir().join("bin")
 }
 
 /// Check if a command exists (either in system PATH or tool bin)
diff --git a/libs/nak/src/dxvk.rs b/libs/nak/src/dxvk.rs
index 97e4222..b335773 100644
--- a/libs/nak/src/dxvk.rs
+++ b/libs/nak/src/dxvk.rs
@@ -1,7 +1,7 @@
 //! DXVK configuration management for Fluorine Manager.
 //!
 //! Downloads dxvk.conf from upstream, appends Fluorine-specific settings,
-//! and stores at `~/.var/app/com.fluorine.manager/config/dxvk.conf`.
+//! and stores at `~/.local/share/fluorine/config/dxvk.conf`.
 
 use std::error::Error;
 use std::fs;
@@ -20,9 +20,7 @@ dxvk.enableGraphicsPipelineLibrary = False
 
 /// Get the path where the DXVK config will be stored.
 pub fn get_dxvk_conf_path() -> PathBuf {
-    let home = std::env::var("HOME").unwrap_or_else(|_| "/tmp".to_string());
-    PathBuf::from(home)
-        .join(".var/app/com.fluorine.manager/config/dxvk.conf")
+    crate::paths::data_dir().join("config/dxvk.conf")
 }
 
 /// Ensure the dxvk.conf file exists, downloading if necessary.
diff --git a/libs/nak/src/lib.rs b/libs/nak/src/lib.rs
index c93f07b..59f41c6 100644
--- a/libs/nak/src/lib.rs
+++ b/libs/nak/src/lib.rs
@@ -7,6 +7,7 @@ pub mod config;
 pub mod dxvk;
 pub mod game_finder;
 pub mod logging;
+pub mod paths;
 pub mod runtime_wrap;
 pub mod steam;
 pub mod utils;
diff --git a/libs/nak/src/logging.rs b/libs/nak/src/logging.rs
index 8c0f91a..e506bf8 100644
--- a/libs/nak/src/logging.rs
+++ b/libs/nak/src/logging.rs
@@ -1,7 +1,7 @@
 //! Logging for Fluorine Manager.
 //!
 //! All log messages are:
-//! 1. Written to `~/.var/app/com.fluorine.manager/logs/nak.log` (always)
+//! 1. Written to `~/.local/share/fluorine/logs/nak.log` (always)
 //! 2. Forwarded to an optional callback set via `set_log_callback()` (for MOBase::log)
 
 use std::fs;
@@ -25,8 +25,7 @@ pub fn set_log_callback(cb: impl Fn(&str, &str) + Send + Sync + 'static) {
 
 /// Get the log directory path.
 fn log_dir() -> PathBuf {
-    let home = std::env::var("HOME").unwrap_or_else(|_| "/tmp".to_string());
-    PathBuf::from(home).join(".var/app/com.fluorine.manager/logs")
+    crate::paths::data_dir().join("logs")
 }
 
 /// Get the log file path.
diff --git a/libs/nak/src/paths.rs b/libs/nak/src/paths.rs
new file mode 100644
index 0000000..4b212b9
--- /dev/null
+++ b/libs/nak/src/paths.rs
@@ -0,0 +1,12 @@
+//! Shared data directory for Fluorine Manager.
+//!
+//! All data lives under `~/.local/share/fluorine/` — accessible from both
+//! native and Flatpak builds (the Flatpak has `--filesystem=home`).
+
+use std::path::PathBuf;
+
+/// Returns the Fluorine data directory (`~/.local/share/fluorine`).
+pub fn data_dir() -> PathBuf {
+    let home = std::env::var("HOME").unwrap_or_else(|_| "/tmp".to_string());
+    PathBuf::from(home).join(".local/share/fluorine")
+}
diff --git a/libs/nak/src/steam/proton.rs b/libs/nak/src/steam/proton.rs
index 064fd96..4059dc4 100644
--- a/libs/nak/src/steam/proton.rs
+++ b/libs/nak/src/steam/proton.rs
@@ -56,8 +56,6 @@ pub fn find_steam_protons() -> Vec<SteamProton> {
         return protons;
     };
 
-    let is_flatpak = steam_path.to_string_lossy().contains(".var/app/com.valvesoftware.Steam");
-
     // 1. Steam's built-in Protons (steamapps/common/Proton*)
     protons.extend(find_builtin_protons(&steam_path));
 
@@ -65,11 +63,8 @@ pub fn find_steam_protons() -> Vec<SteamProton> {
     protons.extend(find_custom_protons(&steam_path));
 
     // 3. System-level Protons in /usr/share/steam/compatibilitytools.d/
-    if is_flatpak {
-        crate::logging::log_info("Flatpak Steam detected - skipping system protons in /usr/share/steam/compatibilitytools.d/");
-    } else {
-        protons.extend(find_system_protons());
-    }
+    //    (Arch packages Proton here; Flatpak has --filesystem=/usr/share/steam:ro)
+    protons.extend(find_system_protons());
 
     // Filter to only include Proton 10+ (required for Steam-native integration)
     protons.retain(is_proton_10_or_newer);
diff --git a/libs/plugin_python/src/mobase/CMakeLists.txt b/libs/plugin_python/src/mobase/CMakeLists.txt
index 2fac52f..3e765dd 100644
--- a/libs/plugin_python/src/mobase/CMakeLists.txt
+++ b/libs/plugin_python/src/mobase/CMakeLists.txt
@@ -5,7 +5,7 @@ if(NOT TARGET mo2::uibase)
   find_package(mo2-uibase CONFIG REQUIRED)
 endif()
 
-pybind11_add_module(mobase MODULE)
+pybind11_add_module(mobase MODULE NO_EXTRAS)
 mo2_default_source_group()
 mo2_configure_target(mobase
 	NO_SOURCES
@@ -38,3 +38,8 @@ mo2_target_sources(mobase
 		./wrappers/wrappers.h
 )
 target_link_libraries(mobase PRIVATE pybind11::qt pybind11::utils mo2::uibase Qt6::Core)
+set_target_properties(mobase PROPERTIES INTERPROCEDURAL_OPTIMIZATION OFF)
+if(NOT MSVC)
+  target_compile_options(mobase PRIVATE -fno-lto)
+  target_link_options(mobase PRIVATE -fno-lto)
+endif()
diff --git a/libs/plugin_python/src/mobase/wrappers/basic_classes.cpp b/libs/plugin_python/src/mobase/wrappers/basic_classes.cpp
index ea69a46..f782099 100644
--- a/libs/plugin_python/src/mobase/wrappers/basic_classes.cpp
+++ b/libs/plugin_python/src/mobase/wrappers/basic_classes.cpp
@@ -575,10 +575,7 @@ namespace mo2::python {
                      mo2::python::show_deprecation_warning(
                          "appVersion", "IOrganizer::appVersion() is deprecated, use "
                                        "IOrganizer::version() instead.");
-#pragma warning(push)
-#pragma warning(disable : 4996)
-                     return o.appVersion();
-#pragma warning(pop)
+                     return o.version();
                  })
             .def("version", &IOrganizer::version)
             .def("createMod", &IOrganizer::createMod,
diff --git a/libs/plugin_python/src/pybind11-qt/CMakeLists.txt b/libs/plugin_python/src/pybind11-qt/CMakeLists.txt
index cb742ad..82793cb 100644
--- a/libs/plugin_python/src/pybind11-qt/CMakeLists.txt
+++ b/libs/plugin_python/src/pybind11-qt/CMakeLists.txt
@@ -56,5 +56,8 @@ add_custom_command(
 add_dependencies(pybind11-qt PyQt6-siph)
 
 target_include_directories(pybind11-qt PRIVATE ${CMAKE_CURRENT_BINARY_DIR})
+if(NOT MSVC)
+	target_compile_options(pybind11-qt PRIVATE -Wno-attributes)
+endif()
 
 add_library(pybind11::qt ALIAS pybind11-qt)
diff --git a/libs/plugin_python/src/pybind11-utils/CMakeLists.txt b/libs/plugin_python/src/pybind11-utils/CMakeLists.txt
index 77895b6..72b0707 100644
--- a/libs/plugin_python/src/pybind11-utils/CMakeLists.txt
+++ b/libs/plugin_python/src/pybind11-utils/CMakeLists.txt
@@ -17,6 +17,11 @@ mo2_configure_target(pybind11-utils
 	TRANSLATIONS OFF
 )
 mo2_default_source_group()
+set_target_properties(pybind11-utils PROPERTIES
+  AUTOMOC OFF
+  AUTOUIC OFF
+  AUTORCC OFF
+)
 target_link_libraries(pybind11-utils PUBLIC pybind11::pybind11)
 target_include_directories(pybind11-utils PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 
diff --git a/libs/plugin_python/src/runner/CMakeLists.txt b/libs/plugin_python/src/runner/CMakeLists.txt
index d164460..9c90314 100644
--- a/libs/plugin_python/src/runner/CMakeLists.txt
+++ b/libs/plugin_python/src/runner/CMakeLists.txt
@@ -22,6 +22,9 @@ mo2_default_source_group()
 target_link_libraries(runner PUBLIC mo2::uibase PRIVATE pybind11::embed pybind11::qt)
 target_include_directories(runner PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_compile_definitions(runner PRIVATE RUNNER_BUILD)
+if(NOT MSVC)
+  target_compile_options(runner PRIVATE -Wno-attributes)
+endif()
 if(NOT WIN32 AND Python_SHARED_LIBRARY)
   get_filename_component(_pylib_name "${Python_SHARED_LIBRARY}" NAME)
   target_compile_definitions(runner PRIVATE
diff --git a/libs/uibase/include/uibase/filterwidget.h b/libs/uibase/include/uibase/filterwidget.h
index b6f09cd..eb1d00f 100644
--- a/libs/uibase/include/uibase/filterwidget.h
+++ b/libs/uibase/include/uibase/filterwidget.h
@@ -24,10 +24,12 @@ class QDLLEXPORT FilterWidgetProxyModel : public QSortFilterProxyModel
 public:
   FilterWidgetProxyModel(FilterWidget& fw, QWidget* parent = nullptr);
   void refreshFilter() {
-#if QT_VERSION >= QT_VERSION_CHECK(6, 9, 0)
+#if QT_VERSION >= QT_VERSION_CHECK(6, 10, 0)
     beginFilterChange();
-#endif
+    endFilterChange(QSortFilterProxyModel::Direction::Rows);
+#else
     invalidateFilter();
+#endif
   }
 
 protected:
diff --git a/libs/uibase/src/utility.cpp b/libs/uibase/src/utility.cpp
index 0ad64ad..e6f53b8 100644
--- a/libs/uibase/src/utility.cpp
+++ b/libs/uibase/src/utility.cpp
@@ -64,7 +64,17 @@ bool removeDir(const QString& dirName)
                dir.entryInfoList(QDir::NoDotAndDotDot | QDir::System | QDir::Hidden |
                                      QDir::AllDirs | QDir::Files,
                                  QDir::DirsFirst)) {
-      if (info.isDir()) {
+      // Never recurse into symlinked directories: in Flatpak they can point to
+      // read-only runtime locations (e.g. /app), and we only want to remove the link.
+      if (info.isSymLink()) {
+        QFile file(info.absoluteFilePath());
+        if (!file.remove()) {
+          reportError(QObject::tr("removal of \"%1\" failed: %2")
+                          .arg(info.absoluteFilePath())
+                          .arg(file.errorString()));
+          return false;
+        }
+      } else if (info.isDir()) {
         if (!removeDir(info.absoluteFilePath())) {
           return false;
         }
@@ -209,7 +219,11 @@ static bool shellOpDelete(const QStringList& fileNames, bool recycle)
   // On Linux, "recycle" moves to trash using Qt; otherwise just delete
   for (const auto& fileName : fileNames) {
     QFileInfo fi(fileName);
-    if (fi.isDir()) {
+    if (fi.isSymLink()) {
+      if (!QFile::remove(fileName)) {
+        return false;
+      }
+    } else if (fi.isDir()) {
       if (!removeDir(fileName)) {
         return false;
       }