feat: add YouTube cookies upload via web UI

Adds a Settings panel to upload a cookies.txt file directly from the
browser, persisted in a named Docker volume. yt-dlp uses the file
when present to bypass YouTube bot detection.

app/main.py

@@ -2,11 +2,12 @@ import os
 from contextlib import asynccontextmanager
 from pathlib import Path
 
-from fastapi import FastAPI, HTTPException, BackgroundTasks
+from fastapi import FastAPI, HTTPException, BackgroundTasks, UploadFile
 from fastapi.responses import FileResponse
 from pydantic import BaseModel
 
 from app import downloader
+from app.config import settings
 
 
 STATIC_DIR = Path(__file__).parent / "static"
@@ -74,6 +75,25 @@ def _delete_file(path):
         pass
 
 
+@app.post("/admin/cookies")
+async def upload_cookies(file: UploadFile):
+    if not settings.yt_dlp_cookies_file:
+        raise HTTPException(status_code=500, detail="YT_DLP_COOKIES_FILE not configured")
+    cookies_path = Path(settings.yt_dlp_cookies_file)
+    cookies_path.parent.mkdir(parents=True, exist_ok=True)
+    content = await file.read()
+    cookies_path.write_bytes(content)
+    return {"status": "ok", "path": str(cookies_path)}
+
+
+@app.get("/admin/cookies/status")
+async def cookies_status():
+    if not settings.yt_dlp_cookies_file:
+        return {"present": False}
+    path = Path(settings.yt_dlp_cookies_file)
+    return {"present": path.exists(), "size": path.stat().st_size if path.exists() else 0}
+
+
 @app.get("/")
 async def index():
     return FileResponse(STATIC_DIR / "index.html")