VFS perf fixes, icon/stylesheet compat, download filename fix

VFS:
- Open backing fd at mo2_open time for read-only handles so mo2_read can
  splice without re-opening the file on every read call.
- Bump RLIMIT_NOFILE at mount time to fit the resulting fd pressure when
  the game keeps hundreds of BSAs open.
- Dedicated node_cache_mutex so resolveByInode / mo2_lookup stop racing
  unordered_map writes while multiple tree_mutex readers are active.
- max_read=1MB + matching conn->max_read and raised max_readahead/max_write
  so the kernel merges Wine's small sequential reads into bigger FUSE
  requests.
- Per-op wall-clock counters in mo2_init() logs so we can distinguish VFS
  latency from game-side work.

Proton launch:
- Write dxvk.conf to the prefix and set DXVK_CONFIG_FILE to force
  dxvk.enableGraphicsPipelineLibrary=False, avoiding long GPL compile
  stalls on first run.

UI / plugin compat:
- Clamp IconDelegate's per-icon width to [8, 16] so narrow content
  columns don't trigger QIcon::pixmap(0,0) returning null and logging
  "failed to load icon" every repaint.
- Pre-create lowercase symlinks in the stylesheet directory so QSS files
  authored on Windows resolve url(foo.svg) when on-disk files are Foo.svg.
- Flip content icons empty-chessboard.png and facegen.png to 8-bit RGBA
  so Qt's built-in PNG reader loads them uniformly.
- Add mobase.Version.canonicalString shim for legacy Python plugins that
  still call the old VersionInfo method on appVersion()'s return.
- BSPluginList: compare normalized plugin name lists instead of byte
  hashes so the post-run case-fix refresh stops spuriously firing the
  "load order changed" dialog.
- BSPluginList disabled by default.

Download manager:
- Parse CDN URL with QUrl + QUrlQuery and read the filename from the
  response-content-disposition query param (RFC 6266 quoted / unquoted /
  ext-value forms), not QFileInfo on the raw URL.
- When the API or URL gives us a CDN object key (no archive extension),
  prefer the actual Content-Disposition header from the live response in
  metaDataChanged and downloadFinished.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/TESData/FileEntry.h b/libs/installer_bsplugins/src/TESData/FileEntry.h
new file mode 100644
index 0000000..0ee6922
--- /dev/null
+++ b/libs/installer_bsplugins/src/TESData/FileEntry.h
@@ -0,0 +1,73 @@
+#ifndef TESDATA_FILEENTRY_H
+#define TESDATA_FILEENTRY_H
+
+#include "Record.h"
+#include "RecordPath.h"
+#include "TESFile/Type.h"
+
+#include <boost/container/flat_map.hpp>
+
+#include <cstdint>
+#include <functional>
+#include <memory>
+#include <optional>
+#include <shared_mutex>
+#include <string>
+#include <variant>
+#include <vector>
+
+namespace cont = boost::container;
+
+namespace TESData
+{
+
+using TESFileHandle = int;
+
+class FileEntry final
+{
+public:
+  struct TreeItem
+  {
+    using Key =
+        std::variant<TESFile::GroupData, std::uint32_t, std::string, TESFile::Type>;
+
+    const TreeItem* parent{nullptr};
+    std::string name;
+    TESFile::Type formType{};
+    std::optional<TESFile::GroupData> group;
+    std::shared_ptr<Record> record;
+    cont::flat_map<Key, std::shared_ptr<TreeItem>> children;
+  };
+
+  FileEntry(TESFileHandle handle, const std::string& name);
+
+  [[nodiscard]] TESFileHandle handle() const { return m_Handle; }
+  [[nodiscard]] const std::string& name() const { return m_Name; }
+  [[nodiscard]] TreeItem* dataRoot() const { return m_Root.get(); }
+  [[nodiscard]] const std::vector<std::string>& files() const { return m_Files; }
+
+  void
+  forEachRecord(std::function<void(const std::shared_ptr<const Record>&)> func) const;
+
+  std::shared_ptr<Record> createRecord(const RecordPath& path, const std::string& name,
+                                       TESFile::Type formType);
+  void addRecord(const RecordPath& path, const std::string& name,
+                 TESFile::Type formType, std::shared_ptr<Record> record);
+  void addChildGroup(const RecordPath&);
+
+  [[nodiscard]] std::shared_ptr<Record> findRecord(const RecordPath& path) const;
+  [[nodiscard]] std::shared_ptr<TreeItem> findItem(const RecordPath& path) const;
+
+private:
+  std::shared_ptr<TreeItem> createHierarchy(const RecordPath& path);
+
+  TESFileHandle m_Handle;
+  std::string m_Name;
+  std::shared_ptr<TreeItem> m_Root;
+  std::vector<std::string> m_Files;
+  mutable std::shared_mutex m_Mutex;
+};
+
+}  // namespace TESData
+
+#endif  // TESDATA_FILEENTRY_H