Add built-in Web UI for media control and monitoring

- Add static file serving to FastAPI application
- Create responsive web interface with real-time updates
- Features:
  - Real-time status updates via WebSocket
  - Album artwork display with automatic updates
  - Playback controls (play, pause, next, previous)
  - Volume control with mute toggle
  - Seekable progress bar
  - Token authentication with localStorage persistence
  - Dark theme and responsive design
  - Auto-reconnect WebSocket support
- Update README with Web UI documentation
- Zero dependencies (vanilla HTML/CSS/JavaScript)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

media_server/main.py

@@ -4,10 +4,13 @@ import argparse
 import logging
 import sys
 from contextlib import asynccontextmanager
+from pathlib import Path
 
 import uvicorn
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import FileResponse
+from fastapi.staticfiles import StaticFiles
 
 from . import __version__
 from .config import settings, generate_default_config, get_config_dir
@@ -69,6 +72,16 @@ def create_app() -> FastAPI:
     app.include_router(media_router)
     app.include_router(scripts_router)
 
+    # Mount static files and serve UI at root
+    static_dir = Path(__file__).parent / "static"
+    if static_dir.exists():
+        app.mount("/static", StaticFiles(directory=str(static_dir)), name="static")
+
+        @app.get("/", include_in_schema=False)
+        async def serve_ui():
+            """Serve the Web UI."""
+            return FileResponse(static_dir / "index.html")
+
     return app