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, 100 insertions, 0 deletions

diff --git a/libs/installer_bsplugins/src/TESData/AssociatedEntry.cpp b/libs/installer_bsplugins/src/TESData/AssociatedEntry.cpp
new file mode 100644
index 0000000..c11697c
--- /dev/null
+++ b/libs/installer_bsplugins/src/TESData/AssociatedEntry.cpp
@@ -0,0 +1,100 @@
+#include "AssociatedEntry.h"
+
+#include <mutex>
+#include <shared_mutex>
+#include <vector>
+
+namespace TESData
+{
+
+AuxItem::AuxItem(const std::string& name, const AuxItem* parent)
+    : m_Name{name}, m_Parent{parent}
+{}
+
+std::shared_ptr<AuxItem> AuxItem::getByIndex(int index) const
+{
+  std::shared_lock lk{m_Mutex};
+
+  if (index < 0 || index >= m_Children.size()) {
+    return nullptr;
+  }
+
+  return m_Children.nth(index)->second;
+}
+
+std::shared_ptr<AuxItem> AuxItem::getByName(const std::string& name) const
+{
+  std::shared_lock lk{m_Mutex};
+
+  const auto it = m_Children.find(name);
+  if (it == m_Children.end()) {
+    return nullptr;
+  }
+
+  return it->second;
+}
+
+int AuxItem::indexOf(const AuxItem* item) const
+{
+  std::shared_lock lk{m_Mutex};
+
+  const auto it = std::ranges::find(m_Children, item, [&](auto&& pair) {
+    return pair.second.get();
+  });
+
+  return static_cast<int>(m_Children.index_of(it));
+}
+
+std::shared_ptr<AuxItem> AuxItem::insert(const std::string& name)
+{
+  std::unique_lock lk{m_Mutex};
+
+  const auto [it, inserted] =
+      m_Children.try_emplace(name, std::make_shared<AuxItem>(name, this));
+  return it->second;
+}
+
+std::shared_ptr<AuxMember> AuxItem::createMember(const std::string& path)
+{
+  std::unique_lock lk{m_Mutex};
+
+  auto& item = m_Member;
+  if (item != nullptr) {
+    return item;
+  }
+
+  item       = std::make_shared<AuxMember>();
+  item->path = path;
+  return item;
+}
+
+void AuxItem::setMember(std::shared_ptr<AuxMember> item)
+{
+  m_Member = item;
+}
+
+AssociatedEntry::AssociatedEntry(const std::string& rootName)
+    : m_Root{std::make_shared<AuxItem>(rootName)}
+{}
+
+void AssociatedEntry::forEachMember(
+    std::function<void(const std::shared_ptr<const AuxMember>&)> func) const
+{
+  std::vector<std::shared_ptr<AuxItem>> stack{m_Root};
+
+  while (!stack.empty()) {
+    const auto item = std::move(stack.back());
+    stack.pop_back();
+
+    if (const auto member = item->member()) {
+      func(member);
+    }
+
+    for (int i = 0; i < item->numChildren(); ++i) {
+      const auto child = item->getByIndex(i);
+      stack.push_back(child);
+    }
+  }
+}
+
+}  // namespace TESData