fix: accurate port banner and tkinter graceful fallback

- Move startup banner into main.py so it shows the actual configured
  port instead of a hardcoded 8080 in the launcher scripts
- Wrap tkinter import in try/except so embedded Python (which lacks
  tkinter) logs a warning instead of crashing the overlay thread

server/src/wled_controller/main.py

@@ -98,6 +98,10 @@ async def lifespan(app: FastAPI):
     logger.info(f"Starting LED Grab v{__version__}")
     logger.info(f"Python version: {sys.version}")
     logger.info(f"Server listening on {config.server.host}:{config.server.port}")
+    print(f"\n  =============================================")
+    print(f"   LED Grab v{__version__}")
+    print(f"   Open http://localhost:{config.server.port} in your browser")
+    print(f"  =============================================\n")
 
     # Validate authentication configuration
     if not config.auth.api_keys: