feat: initial implementation — Arte Concert web GUI

FastAPI backend + HTML/JS frontend pour parcourir et télécharger les
concerts Arte Concert. Cache 6h, recherche live, historique SQLite,
suivi de progression SSE, design sombre Playfair Display + Inter.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

main.py

@@ -0,0 +1,76 @@
+import asyncio
+import json
+import logging
+
+from fastapi import BackgroundTasks, FastAPI, HTTPException, Request
+from fastapi.responses import HTMLResponse, StreamingResponse
+from fastapi.staticfiles import StaticFiles
+from fastapi.templating import Jinja2Templates
+from pydantic import BaseModel
+
+from arte_api import fetch_concerts, invalidate_cache
+from downloader import DownloadManager
+
+logging.basicConfig(level=logging.INFO)
+
+app = FastAPI(title="Arte-dl")
+app.mount("/static", StaticFiles(directory="static"), name="static")
+templates = Jinja2Templates(directory="templates")
+
+dm = DownloadManager()
+
+
+# ------------------------------------------------------------------ pages
+
+
+@app.get("/", response_class=HTMLResponse)
+async def index(request: Request):
+    return templates.TemplateResponse("index.html", {"request": request})
+
+
+# ------------------------------------------------------------------ API: concerts
+
+
+@app.get("/api/concerts")
+async def api_concerts(page: int = 1, search: str = "", page_size: int = 24):
+    return await fetch_concerts(page=page, search=search, page_size=page_size)
+
+
+@app.post("/api/refresh")
+async def api_refresh():
+    count = await invalidate_cache()
+    return {"count": count}
+
+
+# ------------------------------------------------------------------ API: downloads
+
+
+class DownloadRequest(BaseModel):
+    url: str
+    title: str
+
+
+@app.post("/api/download")
+async def api_download(req: DownloadRequest, bg: BackgroundTasks):
+    if not req.url:
+        raise HTTPException(status_code=400, detail="url required")
+    dl_id = dm.enqueue(req.url, req.title, bg)
+    return {"id": dl_id}
+
+
+@app.get("/api/downloads")
+async def api_downloads():
+    return dm.history()
+
+
+@app.get("/api/progress/{dl_id}")
+async def api_progress(dl_id: str):
+    async def stream():
+        while True:
+            s = dm.status(dl_id)
+            yield f"data: {json.dumps(s)}\n\n"
+            if s.get("state") in ("done", "error", "unknown"):
+                break
+            await asyncio.sleep(0.8)
+
+    return StreamingResponse(stream(), media_type="text/event-stream")