fix(release): ship prebuilt assets and bump fallback version

Two release-blocking bugs traced to the same root cause: the unanchored
`data/` rule in .gitignore matched server/src/ledgrab/data/, which is
where shipped package assets live (prebuilt sounds, game adapters).
The files were never `git add`-able without -f, so they never reached
the v0.4.2 tag and CI builds couldn't include them.

- .gitignore: anchor /data/ and /server/data/ so nested package data
  dirs are not ignored.
- Track previously-excluded shipped assets:
  - server/src/ledgrab/data/prebuilt_sounds/{alert,bell,chime,ping,pop}.wav
  - server/src/ledgrab/data/game_adapters/{minecraft,rocket_league,valorant}.yaml
- Bump _FALLBACK_VERSION 0.3.0 -> 0.4.2 to match pyproject.toml.
  The Windows installer strips ledgrab-*.dist-info, so
  importlib.metadata falls back to this literal — which is why
  v0.4.2 reports v0.3.0 in the WebUI.
- Patch _FALLBACK_VERSION at bundle time in build-common.sh and
  build-dist.ps1 so future drift is auto-corrected by the build.

build/build-common.sh

@@ -69,6 +69,16 @@ copy_app_files() {
     # Clean up source maps and __pycache__
     find "$APP_DIR" -name "*.map" -delete 2>/dev/null || true
     find "$APP_DIR" -type d -name __pycache__ -exec rm -rf {} + 2>/dev/null || true
+
+    # Patch the fallback version in the bundled __init__.py. Bundled installs
+    # strip ledgrab-*.dist-info from site-packages, so importlib.metadata
+    # falls back to this literal at runtime — and a stale literal is what
+    # silently shipped v0.4.2 reporting "0.3.0" in the WebUI.
+    local bundled_init="$APP_DIR/src/ledgrab/__init__.py"
+    if [ -f "$bundled_init" ] && [ -n "${VERSION_CLEAN:-}" ]; then
+        sed -i "s/_FALLBACK_VERSION = \"[^\"]*\"/_FALLBACK_VERSION = \"${VERSION_CLEAN}\"/" "$bundled_init"
+        echo "  Patched _FALLBACK_VERSION -> ${VERSION_CLEAN}"
+    fi
 }
 
 # ── Site-packages cleanup ────────────────────────────────────