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, 99 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.cpp b/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.cpp
new file mode 100644
index 0000000..904f049
--- /dev/null
+++ b/libs/installer_bsplugins/src/MOPlugin/IPluginPanel.cpp
@@ -0,0 +1,99 @@
+#include "IPluginPanel.h"
+#include "MOPanelInterface.h"
+
+#include <QTabWidget>
+
+using namespace Qt::Literals::StringLiterals;
+
+IPluginPanel::Position IPluginPanel::Position::before(const QString& panelName)
+{
+  return {Order::Before, panelName};
+}
+
+IPluginPanel::Position IPluginPanel::Position::after(const QString& panelName)
+{
+  return {Order::After, panelName};
+}
+
+IPluginPanel::Position IPluginPanel::Position::inPlaceOf(const QString& panelName)
+{
+  return {Order::InPlaceOf, panelName};
+}
+
+IPluginPanel::Position IPluginPanel::Position::atStart()
+{
+  return {Order::AtStart, {}};
+}
+
+IPluginPanel::Position IPluginPanel::Position::atEnd()
+{
+  return {Order::AtEnd, {}};
+}
+
+bool IPluginPanel::init(MOBase::IOrganizer* organizer)
+{
+  if (organizer == nullptr) {
+    return false;
+  }
+
+  organizer->onUserInterfaceInitialized([this, organizer](QMainWindow* mainWindow) {
+    const auto tabWidget = mainWindow->findChild<QTabWidget*>(u"tabWidget"_s);
+
+    if (tabWidget == nullptr) {
+      return;
+    }
+
+    const auto intfc    = new MOPanelInterface(organizer, mainWindow);
+    const auto widget   = this->createWidget(intfc, tabWidget);
+    const auto label    = this->label();
+    const auto position = this->position();
+
+    switch (position.order_) {
+    case Order::Before: {
+      const auto refTab = !position.reference_.isNull()
+                              ? tabWidget->findChild<QWidget*>(position.reference_)
+                              : nullptr;
+      if (refTab != nullptr) {
+        if (const int index = tabWidget->indexOf(refTab); index != -1) {
+          const int currentIndex = tabWidget->currentIndex();
+          tabWidget->insertTab(index, widget, label);
+          if (index <= currentIndex) {
+            tabWidget->setCurrentIndex(currentIndex);
+          }
+        }
+        break;
+      }
+    }
+      [[fallthrough]];
+    case Order::AtStart: {
+      const int currentIndex = tabWidget->currentIndex();
+      tabWidget->insertTab(0, widget, label);
+      tabWidget->setCurrentIndex(currentIndex);
+    } break;
+    case Order::InPlaceOf:
+    case Order::After: {
+      const auto refTab = !position.reference_.isNull()
+                              ? tabWidget->findChild<QWidget*>(position.reference_)
+                              : nullptr;
+
+      if (refTab != nullptr) {
+        if (const int index = tabWidget->indexOf(refTab); index != -1) {
+          tabWidget->insertTab(index + 1, widget, label);
+          if (position.order_ == Order::InPlaceOf) {
+            tabWidget->removeTab(index);
+          }
+        }
+        break;
+      }
+    }
+      [[fallthrough]];
+    case Order::AtEnd: {
+      tabWidget->addTab(widget, label);
+    } break;
+    }
+
+    intfc->assignWidget(tabWidget, widget);
+  });
+
+  return this->initPlugin(organizer);
+}