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/docs/AUTHENTICATION.md

@@ -1,6 +1,6 @@
 # API Authentication Guide
 
-WLED Screen Controller **requires** API key authentication for all API endpoints. This ensures your server is secure and all access is properly authenticated and audited.
+LedGrab **requires** API key authentication for all API endpoints. This ensures your server is secure and all access is properly authenticated and audited.
 
 ## Configuration
 
@@ -66,7 +66,7 @@ curl -H "Authorization: Bearer your-api-key-here" \
 The integration will prompt for an API key during setup if authentication is enabled. You can also configure it in `configuration.yaml`:
 
 ```yaml
-wled_screen_controller:
+ledgrab:
   server_url: "http://192.168.1.100:8080"
   api_key: "your-api-key-here"  # Optional, only if auth is enabled
 ```
@@ -168,8 +168,8 @@ export WLED_API_KEY_2="$(openssl rand -hex 32)"
 services:
   wled-controller:
     environment:
-      - WLED_AUTH__ENABLED=true
-      - WLED_AUTH__API_KEYS__0=your-key-here
+      - LEDGRAB_AUTH__ENABLED=true
+      - LEDGRAB_AUTH__API_KEYS__0=your-key-here
 ```
 
 Or use Docker secrets for better security.