fix(wasm): KiCad 10 kiplatform/libgit2 stubs, e2e fixtures, asyncify -g hook

- wasm/kiplatform: add EnableDarkMode, IO::TimestampDir, UI::AllowNetworkFileSystems,
  UI::CancelPendingScroll, SECRETS::DeleteSecret (new KiCad 10 functions).
- wasm/stubs/libgit2_stub.c: ~156 no-op stubs for KiCad 10's restructured git
  backend + git-backed local history + text_eval VCS.
- tests/kicad: bump the demo project dir 9.99 -> 10.0 (KiCad 10 stores projects
  under /home/kicad/documents/kicad/10.0/) — fixes load-pcb + 3d-viewer e2e.
- scripts/common/apply-asyncify.sh: ASYNCIFY_EXTRA_OPTS hook (e.g. -g for
  symbolizable wasm traces).
- kicad submodule -> ef00c2d3 (KiCad 10 link + runtime adaptations).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

wasm/kiplatform/io.cpp

@@ -6,7 +6,9 @@
 #include <kiplatform/io.h>
 #include <wx/string.h>
 #include <wx/filename.h>
+#include <wx/dir.h>
 #include <stdio.h>
+#include <sys/stat.h>
 
 namespace KIPLATFORM
 {
@@ -45,5 +47,38 @@ void LongPathAdjustment( wxFileName& aFilename )
     // No-op on non-Windows platforms
 }
 
+long long TimestampDir( const wxString& aDirPath, const wxString& aFilespec )
+{
+    // Mirror the native implementations: accumulate (mtime, size) over files
+    // matching the spec so callers can detect library-directory changes. The
+    // Emscripten virtual filesystem supports stat(), so this works for MEMFS-
+    // backed local libraries (git/network libraries are handled JS-side).
+    long long timestamp = 0;
+
+    wxDir dir( aDirPath );
+
+    if( !dir.IsOpened() )
+        return timestamp;
+
+    wxString filename;
+    bool     cont = dir.GetFirst( &filename, aFilespec, wxDIR_FILES );
+
+    while( cont )
+    {
+        wxString    fullPath = aDirPath + wxFILE_SEP_PATH + filename;
+        struct stat entryStat;
+
+        if( stat( fullPath.fn_str(), &entryStat ) == 0 )
+        {
+            timestamp += static_cast<long long>( entryStat.st_mtime ) * 1000;
+            timestamp += entryStat.st_size;
+        }
+
+        cont = dir.GetNext( &filename );
+    }
+
+    return timestamp;
+}
+
 } // namespace IO
 } // namespace KIPLATFORM