perf: pre-compile Python bytecode in portable build

Add compileall step to build-dist-windows.sh that generates .pyc files
for both app source and site-packages. Saves ~100-200ms on startup by
skipping parse/compile on first import.

build-dist-windows.sh

@@ -348,6 +348,11 @@ mkdir -p "$DIST_DIR/data" "$DIST_DIR/logs"
 find "$APP_DIR" -name "*.map" -delete 2>/dev/null || true
 find "$APP_DIR" -type d -name __pycache__ -exec rm -rf {} + 2>/dev/null || true
 
+# Pre-compile Python bytecode for faster startup
+echo "  Pre-compiling Python bytecode..."
+python -m compileall -b -q "$APP_DIR/src" 2>/dev/null || true
+python -m compileall -b -q "$SITE_PACKAGES" 2>/dev/null || true
+
 # ── Create launcher ──────────────────────────────────────────
 
 echo "[8b/9] Creating launcher and packaging..."