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, 89 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/GUI/IconDelegate.cpp b/libs/installer_bsplugins/src/GUI/IconDelegate.cpp
new file mode 100644
index 0000000..ff99405
--- /dev/null
+++ b/libs/installer_bsplugins/src/GUI/IconDelegate.cpp
@@ -0,0 +1,89 @@
+#include "IconDelegate.h"
+
+#include <QDebug>
+#include <QHBoxLayout>
+#include <QHeaderView>
+#include <QLabel>
+#include <QPainter>
+#include <QPixmapCache>
+#include <algorithm>
+#include <log.h>
+
+namespace GUI
+{
+
+using namespace MOBase;
+
+constexpr int MAX_WIDTH = 16;
+constexpr int MARGIN_X  = 4;
+
+IconDelegate::IconDelegate(QTreeView* view, int column, int compactSize)
+    : QStyledItemDelegate(view), m_Column{column}, m_CompactSize{compactSize},
+      m_Compact{false}
+{
+  if (view) {
+    connect(view->header(), &QHeaderView::sectionResized,
+            [=](int logicalIndex, [[maybe_unused]] int oldSize, int newSize) {
+              if (logicalIndex == m_Column) {
+                m_Compact = newSize < m_CompactSize;
+              }
+            });
+  }
+}
+
+void IconDelegate::paintIcons(QPainter* painter, const QStyleOptionViewItem& option,
+                              [[maybe_unused]] const QModelIndex& index,
+                              const QList<QString>& icons)
+{
+  int x = MARGIN_X;
+  painter->save();
+
+  int iconWidth =
+      icons.size() > 0 ? ((option.rect.width() / icons.size()) - MARGIN_X) : MAX_WIDTH;
+  // Clamp to at least 8px so narrow columns don't make QIcon::pixmap()
+  // return null and spuriously log "failed to load icon".
+  iconWidth = std::clamp(iconWidth, 8, MAX_WIDTH);
+
+  const int margin = (option.rect.height() - iconWidth) / 2;
+
+  painter->translate(option.rect.topLeft());
+  for (const QString& iconId : icons) {
+    if (iconId.isEmpty()) {
+      x += iconWidth + MARGIN_X;
+      continue;
+    }
+    QPixmap icon;
+    const QString fullIconId = QString("%1_%2").arg(iconId).arg(iconWidth);
+    if (!QPixmapCache::find(fullIconId, &icon)) {
+      icon = QIcon(iconId).pixmap(iconWidth, iconWidth);
+      if (icon.isNull()) {
+        log::warn("failed to load icon {}", iconId);
+      }
+      QPixmapCache::insert(fullIconId, icon);
+    }
+    painter->drawPixmap(x, margin, iconWidth, iconWidth, icon);
+    x += iconWidth + MARGIN_X;
+  }
+
+  painter->restore();
+}
+
+void IconDelegate::paint(QPainter* painter, const QStyleOptionViewItem& option,
+                         const QModelIndex& index) const
+{
+  if (auto* const w = qobject_cast<QAbstractItemView*>(parent())) {
+    w->itemDelegate()->paint(painter, option, index);
+  } else {
+    QStyledItemDelegate::paint(painter, option, index);
+  }
+
+  paintIcons(painter, option, index, getIcons(index));
+}
+
+QSize IconDelegate::sizeHint(const QStyleOptionViewItem& option,
+                             const QModelIndex& index) const
+{
+  return QSize(getNumIcons(index) * (MAX_WIDTH + MARGIN_X), option.rect.height());
+}
+
+}  // namespace GUI