Add runtime resource loading and fix Docker incremental builds

- Build images.tar.gz bitmap archive for KiCad icons
- Fetch resources at runtime via HTTP instead of bundling in WASM
- Write to Emscripten virtual FS at compile-time KICAD_DATA path
- Fix rsync timestamp handling for correct make change detection
- Update kicad submodule with WASM settings manager fix

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker/entrypoint.sh

@@ -7,12 +7,16 @@ source /emsdk/emsdk_env.sh 2>/dev/null
 # Sync source from host to workspace volume
 # This fixes macOS Docker timestamp issues with bind mounts
 # (autoconf sanity checks fail when timestamps appear inconsistent)
+# Touch transferred files to set container timestamps for correct make detection
 if [[ -d /workspace-host ]]; then
     echo "Syncing source code to container volume..."
-    rsync -a --delete \
+    rsync -ai --delete \
         --exclude='build-wasm' \
         --exclude='output' \
-        /workspace-host/ /workspace/
+        /workspace-host/ /workspace/ | \
+        grep "^>f" | \
+        sed "s/^[^ ]* //" | \
+        while read f; do touch "/workspace/$f" 2>/dev/null; done
     echo "Sync complete."
 fi