refactor: rename project to LedGrab, split HA integration into separate repo

- Rename Python package: wled_controller -> ledgrab
- Rename env var prefix: WLED_ -> LEDGRAB_ (with auto-migration for old vars)
- Rename localStorage key: wled_api_key -> ledgrab_api_key (with migration)
- Rename HA integration domain: wled_screen_controller -> ledgrab
- Update all imports, build scripts, Docker, installer, config, docs
- Remove HA integration (moved to ledgrab-haos-integration repo)
- Remove hacs.json (belongs in HA repo now)
- Add startup warning for users with old WLED_ env vars
- All tests pass (715/715), ruff clean, tsc clean, frontend builds

server/tests/api/routes/test_system_routes.py

@@ -8,7 +8,7 @@ without setting up the full dependency injection.
 import pytest
 from fastapi.testclient import TestClient
 
-from wled_controller import __version__
+from ledgrab import __version__
 
 
 @pytest.fixture(scope="module")
@@ -18,7 +18,7 @@ def client():
     The app module initializes stores from the default config on import,
     which is acceptable for read-only endpoints tested here.
     """
-    from wled_controller.main import app
+    from ledgrab.main import app
 
     return TestClient(app, raise_server_exceptions=False)