Remove AppImage build target and runtime references

We ship via portable tarball directory + .bin self-extracting installer
only; the AppImage path was unmaintained and pulling in linuxdeploy
tooling for a format we no longer publish.

Build:
- build.sh: drop appimage/all-includes-appimage modes (now: tarball,
  installer, all=both, shell). Output listing tracks the directory.
- docker/Dockerfile: drop BUILD_APPIMAGE arg and the linuxdeploy
  download/extract block.
- docker/build-inner.sh: drop build_appimage() (~120 lines), AppImage
  arm of the BUILD_MODE switch, *.AppImage summary listing.
- docker/AppRun.sh: deleted.
- .gitignore: drop *.AppImage / squashfs-root / *.flatpak entries.

Runtime: no longer key off APPIMAGE/APPDIR env vars or AppRun-set
state. The fluorine-manager launcher script already exports
FLUORINE_ORIG_*, MO2_BASE_DIR, MO2_PLUGINS_DIR, MO2_LIBS_DIR,
MO2_PYTHON_DIR for the same purpose, so simplify:
- envshortcut: appImageOrBinary -> launcherOrBinary; bundledFluorineIcon
  no longer probes APPDIR.
- nxmhandler: drop APPIMAGE-based wrapper path; use applicationFilePath.
- protonlauncher: rename cleanAppImageEnv -> cleanFluorineEnv, drop
  APPIMAGE/APPDIR/OWD/ARGV0/APPIMAGE_ORIGINAL_EXEC/DESKTOPINTEGRATION
  removals and .mount_Fluori pattern strip.
- prefixsetuprunner: same env-cleaning trim.
- utility, library.h, proxypython, mainwindow, moapplication, appconfig:
  comment cleanup pointing at the launcher instead of AppRun.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

3 files changed, 14 insertions, 12 deletions

diff --git a/libs/archive/src/library.h b/libs/archive/src/library.h
index a0656f2..e182f08 100644
--- a/libs/archive/src/library.h
+++ b/libs/archive/src/library.h
@@ -94,7 +94,7 @@ private:
         exeDir = exeDir.substr(0, slash);
     }
 
-    // AppImage: check MO2_LIBS_DIR env var first (writable dir next to AppImage)
+    // Honor MO2_LIBS_DIR (set by the fluorine-manager launcher) first.
     std::string envLibs;
     const char* envVal = std::getenv("MO2_LIBS_DIR");
     if (envVal && envVal[0] != '\0') {
diff --git a/libs/plugin_python/src/proxy/proxypython.cpp b/libs/plugin_python/src/proxy/proxypython.cpp
index 6e4acad..56d9dae 100644
--- a/libs/plugin_python/src/proxy/proxypython.cpp
+++ b/libs/plugin_python/src/proxy/proxypython.cpp
@@ -167,9 +167,10 @@ bool ProxyPython::init(IOrganizer* moInfo)
             std::filesystem::path{IOrganizer::getPluginDataPath().toStdWString()}};
         m_Runner->initialize(paths);
 #else
-        // On Linux, rely on the unpacked stdlib from PYTHONHOME (AppRun sets
-        // MO2_PYTHON_DIR/PYTHONHOME). Do not prepend pythoncore.zip here:
-        // forcing zipimport can fail when zlib is unavailable in embedded mode.
+        // On Linux, rely on the unpacked stdlib from PYTHONHOME (the
+        // fluorine-manager launcher sets MO2_PYTHON_DIR/PYTHONHOME). Do not
+        // prepend pythoncore.zip here: forcing zipimport can fail when zlib
+        // is unavailable in embedded mode.
         std::vector<fs::path> paths{
             libpath,
             std::filesystem::path{IOrganizer::getPluginDataPath().toStdWString()}};
@@ -184,9 +185,9 @@ bool ProxyPython::init(IOrganizer* moInfo)
             }
         }
 
-        // Allow portable/AppImage builds to ship Python packages next to the app.
-        // MO2_PYTHON_DIR (set by AppRun) points to the writable python/ dir
-        // next to the AppImage; fall back to <exe_dir>/python.
+        // Allow portable builds to ship Python packages next to the app.
+        // MO2_PYTHON_DIR (set by the fluorine-manager launcher) points to the
+        // writable python/ dir; fall back to <exe_dir>/python.
         fs::path pythonDir;
         const char* envPy = std::getenv("MO2_PYTHON_DIR");
         if (envPy && envPy[0] != '\0') {
diff --git a/libs/uibase/src/utility.cpp b/libs/uibase/src/utility.cpp
index 40774ae..4304561 100644
--- a/libs/uibase/src/utility.cpp
+++ b/libs/uibase/src/utility.cpp
@@ -396,16 +396,16 @@ namespace shell
     }
   }
 
-  // Launch an external host process with AppImage environment variables
-  // cleaned up, so tools like xdg-open/kde-open use the host's own
-  // libraries and Qt plugins instead of the bundled ones.
+  // Launch an external host process with bundled-runtime environment
+  // variables cleaned up, so tools like xdg-open/kde-open use the host's
+  // own libraries and Qt plugins instead of the ones we ship.
   static bool startDetachedHostProcess(const QString& program,
                                        const QStringList& args)
   {
     QProcess proc;
     auto env = QProcessEnvironment::systemEnvironment();
 
-    // Restore original LD_LIBRARY_PATH (saved by AppRun.sh)
+    // Restore original LD_LIBRARY_PATH (saved by the fluorine-manager launcher).
     if (env.contains(QStringLiteral("FLUORINE_ORIG_LD_LIBRARY_PATH"))) {
       const auto orig = env.value(QStringLiteral("FLUORINE_ORIG_LD_LIBRARY_PATH"));
       if (orig.isEmpty())
@@ -414,7 +414,8 @@ namespace shell
         env.insert(QStringLiteral("LD_LIBRARY_PATH"), orig);
     }
 
-    // Remove AppImage-specific Qt/path variables that would confuse host apps
+    // Remove Qt/path variables pointing at our bundled runtime that would
+    // confuse host apps.
     env.remove(QStringLiteral("QT_PLUGIN_PATH"));
     env.remove(QStringLiteral("QT_QPA_PLATFORM_PLUGIN_PATH"));
     env.remove(QStringLiteral("QTWEBENGINEPROCESS_PATH"));