controller: Phase 6+ — Web UI mini dashboard

Static HTML/JS dashboard в cuda_grid_controller/static/index.html, mounted
на /ui и / FastAPI endpoints. Vanilla JS + HLS.js (CDN) для video player.

Controls:
  Audio source — buttons из /audio/{instance} list, switch через POST
  Intercom — Start (music↓) / End (restore)
  Snapshot — opens PNG в new tab
  Manual overlay — form для rect/text/dim/icon types
  Chat — placeholder (info-toast про mosquitto_pub)
  State — refresh каждые 2 sec, shows layout/overlays_count + raw list

Player consumes HLS на http://server:8888/live/index.m3u8 (mediamtx).
TV не нужен — браузер на любом устройстве в LAN.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

controller/cuda_grid_controller/http_api.py

@@ -3,11 +3,13 @@
 from __future__ import annotations
 
 import asyncio
+from pathlib import Path
 from typing import Any
 
 import structlog
 from fastapi import Body, FastAPI, HTTPException
-from fastapi.responses import Response
+from fastapi.responses import FileResponse, Response
+from fastapi.staticfiles import StaticFiles
 from pydantic import BaseModel, TypeAdapter
 
 from .config import Config
@@ -36,6 +38,15 @@ def create_app(
         description="Control plane для vf_cuda_grid FFmpeg filter",
     )
 
+    # Static UI — http://controller:8080/ui/
+    static_dir = Path(__file__).parent / "static"
+    if static_dir.exists():
+        app.mount("/ui", StaticFiles(directory=str(static_dir), html=True), name="ui")
+
+        @app.get("/")
+        async def root_redirect():
+            return FileResponse(static_dir / "index.html")
+
     def _check_instance(name: str):
         inst = next((i for i in cfg.instances if i.name == name), None)
         if inst is None: