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, 115 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/TESData/FormParser.h b/libs/installer_bsplugins/src/TESData/FormParser.h
new file mode 100644
index 0000000..b0220a0
--- /dev/null
+++ b/libs/installer_bsplugins/src/TESData/FormParser.h
@@ -0,0 +1,115 @@
+#ifndef TESDATA_FORMPARSER_H
+#define TESDATA_FORMPARSER_H
+
+#include "DataItem.h"
+#include "TESFile/Stream.h"
+#include "TESFile/Type.h"
+
+#include <coroutine>
+#include <istream>
+#include <map>
+#include <memory>
+#include <span>
+#include <string>
+
+using namespace Qt::Literals::StringLiterals;
+
+namespace TESData
+{
+
+namespace Parse
+{
+  struct Promise;
+
+  struct Task : std::coroutine_handle<Promise>
+  {
+    using promise_type = Promise;
+
+    Task(std::coroutine_handle<Promise>&& promise)
+        : std::coroutine_handle<Promise>::coroutine_handle(promise)
+    {}
+  };
+
+  struct Promise
+  {
+    Task get_return_object() { return {Task::from_promise(*this)}; }
+    std::suspend_always initial_suspend() noexcept { return {}; }
+    std::suspend_always final_suspend() noexcept { return {}; }
+    void return_void() {}
+    void unhandled_exception() {}
+  };
+}  // namespace Parse
+
+using ParseTask = Parse::Task;
+
+class IFormParser
+{
+public:
+  virtual void parseFlags(DataItem* root, int fileIndex, std::uint32_t flags) const = 0;
+
+  virtual ParseTask parseForm(DataItem* root, int fileIndex, bool localized,
+                              std::span<const std::string> masters,
+                              const std::string& plugin, const TESFile::Type& signature,
+                              std::istream* const& stream) const = 0;
+};
+
+class FormParserManager final
+{
+  template <typename T, TESFile::Type Type>
+  friend struct RegisterFormParser;
+
+public:
+  enum class Game
+  {
+    TES4,
+    FO3,
+    FNV,
+    TES5,
+    FO4,
+    SSE,
+
+    Unknown
+  };
+
+  FormParserManager() = delete;
+
+  [[nodiscard]] static std::shared_ptr<const IFormParser> getParser(Game game,
+                                                                    TESFile::Type type);
+
+private:
+  using RegistrationMap = std::map<TESFile::Type, std::shared_ptr<IFormParser>>;
+
+  static auto registrationMap() -> RegistrationMap&;
+};
+
+template <typename T, TESFile::Type Type>
+struct [[maybe_unused]] RegisterFormParser
+{
+  explicit RegisterFormParser()
+  {
+    FormParserManager::registrationMap().emplace(Type, std::make_shared<T>());
+  }
+};
+
+template <TESFile::Type Type = {}>
+class FormParser : public IFormParser
+{
+  inline static RegisterFormParser<FormParser<Type>, Type> reg{};
+
+public:
+  void parseFlags(DataItem* root, int fileIndex, std::uint32_t flags) const override;
+
+  ParseTask parseForm(DataItem* root, int fileIndex, bool localized,
+                      std::span<const std::string> masters, const std::string& plugin,
+                      const TESFile::Type& signature,
+                      std::istream* const& stream) const override;
+};
+
+QString readBytes(std::istream& stream, int size);
+QString readLstring(bool localized, std::istream& stream);
+QString readFormId(std::span<const std::string> masters, const std::string& plugin,
+                   std::istream& stream);
+
+}  // namespace TESData
+
+#endif  // TESDATA_FORMPARSER_H