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, 83 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/BSPluginInfo/AuxTreeModel.cpp b/libs/installer_bsplugins/src/BSPluginInfo/AuxTreeModel.cpp
new file mode 100644
index 0000000..b5df2ab
--- /dev/null
+++ b/libs/installer_bsplugins/src/BSPluginInfo/AuxTreeModel.cpp
@@ -0,0 +1,83 @@
+#include "AuxTreeModel.h"
+
+namespace BSPluginInfo
+{
+
+AuxTreeModel::AuxTreeModel(const TESData::AssociatedEntry* entry, QObject* parent)
+    : QAbstractItemModel(parent), m_Entry{entry}
+{}
+
+QModelIndex AuxTreeModel::index(int row, int column, const QModelIndex& parent) const
+{
+  if (row < 0 || column != 0) {
+    return QModelIndex();
+  }
+
+  const auto parentItem = parent.isValid()
+                              ? static_cast<const Item*>(parent.internalPointer())
+                              : m_Entry->root().get();
+
+  const auto item = parentItem->getByIndex(row).get();
+  return item ? createIndex(row, column, item) : QModelIndex();
+}
+
+QModelIndex AuxTreeModel::parent(const QModelIndex& index) const
+{
+  if (!index.isValid())
+    return QModelIndex();
+
+  const auto item   = static_cast<const Item*>(index.internalPointer());
+  const auto parent = item ? item->parent() : nullptr;
+  if (!parent || !parent->parent()) {
+    return QModelIndex();
+  }
+
+  const int row = parent->parent()->indexOf(parent);
+
+  return createIndex(row, 0, parent);
+}
+
+int AuxTreeModel::rowCount(const QModelIndex& parent) const
+{
+  const auto parentItem = parent.isValid()
+                              ? static_cast<const Item*>(parent.internalPointer())
+                              : m_Entry->root().get();
+
+  return parentItem ? parentItem->numChildren() : 0;
+}
+
+int AuxTreeModel::columnCount([[maybe_unused]] const QModelIndex& parent) const
+{
+  return 1;
+}
+
+QVariant AuxTreeModel::data(const QModelIndex& index, int role) const
+{
+  if (!index.isValid()) {
+    return QVariant();
+  }
+
+  const auto item = static_cast<const Item*>(index.internalPointer());
+  switch (role) {
+  case Qt::DisplayRole:
+    return QString::fromStdString(item->name());
+  }
+
+  return QVariant();
+}
+
+QVariant AuxTreeModel::headerData(int section, Qt::Orientation orientation,
+                                  int role) const
+{
+  if (orientation != Qt::Horizontal || role != Qt::DisplayRole) {
+    return QVariant();
+  }
+
+  if (section == 0) {
+    return tr("File Name");
+  } else {
+    return QVariant();
+  }
+}
+
+}  // namespace BSPluginInfo