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, 118 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/BSPluginList/PluginGroupProxyModel.h b/libs/installer_bsplugins/src/BSPluginList/PluginGroupProxyModel.h
new file mode 100644
index 0000000..c0f0f1c
--- /dev/null
+++ b/libs/installer_bsplugins/src/BSPluginList/PluginGroupProxyModel.h
@@ -0,0 +1,118 @@
+#ifndef BSPLUGINLIST_PLUGINGROUPPROXYMODEL_H
+#define BSPLUGINLIST_PLUGINGROUPPROXYMODEL_H
+
+#include "TESData/FileInfo.h"
+
+#include <imoinfo.h>
+
+#include <boost/container/flat_map.hpp>
+
+#include <QAbstractProxyModel>
+
+#include <limits>
+#include <memory>
+#include <vector>
+
+namespace BSPluginList
+{
+
+class PluginGroupProxyModel final : public QAbstractProxyModel
+{
+  Q_OBJECT
+
+public:
+  explicit PluginGroupProxyModel(MOBase::IOrganizer* organizer,
+                                 QObject* parent = nullptr);
+
+  void setSourceModel(QAbstractItemModel* sourceModel) override;
+
+  bool hasChildren(const QModelIndex& parent = QModelIndex()) const override;
+  int rowCount(const QModelIndex& parent = QModelIndex()) const override;
+  int columnCount(const QModelIndex& parent = QModelIndex()) const override;
+
+  QModelIndex index(int row, int column,
+                    const QModelIndex& parent = QModelIndex()) const override;
+  QModelIndex parent(const QModelIndex& index) const override;
+
+  QModelIndex mapFromSource(const QModelIndex& sourceIndex) const override;
+  QModelIndex mapToSource(const QModelIndex& proxyIndex) const override;
+
+  Qt::ItemFlags flags(const QModelIndex& index) const override;
+  QVariant data(const QModelIndex& index, int role = Qt::DisplayRole) const override;
+  bool setData(const QModelIndex& index, const QVariant& value,
+               int role = Qt::EditRole) override;
+  QModelIndex buddy(const QModelIndex& index) const override;
+  QVariant headerData(int section, Qt::Orientation orientation,
+                      int role = Qt::DisplayRole) const override;
+
+  QMimeData* mimeData(const QModelIndexList& indexes) const override;
+  bool canDropMimeData(const QMimeData* data, Qt::DropAction action, int row,
+                       int column, const QModelIndex& parent) const override;
+  bool dropMimeData(const QMimeData* data, Qt::DropAction action, int row, int column,
+                    const QModelIndex& parent) override;
+
+  void setDroppingBelowExpandedItem(bool value) { m_DroppingBelowExpandedItem = value; }
+
+signals:
+  void groupRenameRequested(const QModelIndex& index, const QString& name);
+
+private slots:
+  void onSourceDataChanged(const QModelIndex& topLeft, const QModelIndex& bottomRight,
+                           const QList<int>& roles = QList<int>());
+  void onSourceLayoutChanged(
+      const QList<QPersistentModelIndex>& parents = QList<QPersistentModelIndex>(),
+      QAbstractItemModel::LayoutChangeHint hint =
+          QAbstractItemModel::NoLayoutChangeHint);
+  void onSourceModelReset();
+  void onSourceRowsInserted(const QModelIndex& parent);
+  void onSourceRowsRemoved(const QModelIndex& parent);
+
+private:
+  static constexpr std::size_t NO_ID = std::numeric_limits<std::size_t>::max();
+
+  struct Group
+  {
+    QString name;
+    std::vector<std::size_t> children;
+
+    explicit Group(const QString& name) : name{name} {}
+  };
+
+  struct ProxyItem
+  {
+    int row;
+    int sourceRow;
+    std::size_t parentId;
+    std::shared_ptr<Group> groupInfo;
+
+    [[nodiscard]] bool isSourceItem() const { return sourceRow != -1; }
+    [[nodiscard]] bool isGroup() const { return groupInfo != nullptr; }
+    [[nodiscard]] bool isDivider() const
+    {
+      return groupInfo == nullptr && sourceRow == -1;
+    }
+  };
+
+  [[nodiscard]] int mapLowerBoundToSourceRow(std::size_t id) const;
+  [[nodiscard]] bool isAboveDivider(std::size_t id) const;
+  [[nodiscard]] bool isBelowDivider(std::size_t id) const;
+
+  void buildGroups();
+  [[nodiscard]] std::size_t createItem(const QString& name, int row, int sourceRow,
+                                       std::size_t parent, std::shared_ptr<Group> group,
+                                       int repeat = 0);
+
+  std::vector<ProxyItem> m_ProxyItems;
+  boost::container::flat_multimap<QString, std::size_t> m_ItemMap;
+  std::vector<std::size_t> m_TopLevel;
+  std::vector<std::size_t> m_SourceMap;
+
+  bool m_DroppingBelowExpandedItem;
+  mutable std::vector<std::size_t> m_DraggingGroups;
+
+  MOBase::IOrganizer* m_Organizer;
+};
+
+}  // namespace BSPluginList
+
+#endif  // BSPLUGINLIST_PLUGINGROUPPROXYMODEL_H