fix: A21 phase 1 — 352 routes async sans await → threadpool (v7.8.0)

- Conversion `async def` → `def` de TOUTES les routes dont le corps ne contient
  ni `await`, ni `async with`, ni `async for`, ni `asyncio` (scan automatique
  corps par corps sur app/ : 352 converties, 0 dangereuses, vérifié
  `asyncio`/`run_coroutine`/`.result()` absents). FastAPI exécute ces handlers
  dans son threadpool → tout leur SQLite (`get_conn()` + `conn.execute`) quitte
  l'event loop, sans changer une ligne de logique.
- Répartition : api_v2 60, dashboard 40, collections 25, board 23,
  workspace 19, wiki 17, permissions 14, api 14, main.py 6, + 35 fichiers.
- Les 4 routers prioritaires de l'audit sont couverts par ce lot :
  api_v2 60 + dashboard 40 + collections 25 + board 23 = 148 conversions
  (le reste de leurs routes attend la phase 2 : elles ont de vrais `await`).
- Reste (phase 2) : les 311 routes avec de vrais `await` → enrouler les blocs
  DB dans `await anyio.to_thread.run_sync(...)` ; pas de wrapper partagé livré
  (rien ne l'appellerait — YAGNI jusqu'au premier usage).

suite **1037/1037** (233 s) · `ruff check app tests` OK · docs à jour

app/routers/workers.py

@@ -72,7 +72,7 @@ async def create_worker(request: Request):
 
 
 @router.get("/api/v2/workers")
-async def list_workers(request: Request):
+def list_workers(request: Request):
     _auth_user(request)
     limit, offset = parse_pagination(request)
     with get_conn() as conn:
@@ -87,7 +87,7 @@ async def list_workers(request: Request):
 
 
 @router.get("/api/v2/workers/{worker_id}")
-async def get_worker(worker_id: int, request: Request):
+def get_worker(worker_id: int, request: Request):
     user = _auth_user(request)
     with get_conn() as conn:
         row = conn.execute("SELECT * FROM workers WHERE id=?", (worker_id,)).fetchone()
@@ -146,7 +146,7 @@ async def update_worker(worker_id: int, request: Request):
 
 
 @router.delete("/api/v2/workers/{worker_id}")
-async def delete_worker(worker_id: int, request: Request):
+def delete_worker(worker_id: int, request: Request):
     user = _auth_user(request, require_write=True)
     with get_conn() as conn:
         row = conn.execute("SELECT * FROM workers WHERE id=?", (worker_id,)).fetchone()
@@ -186,7 +186,7 @@ async def run_worker_endpoint(worker_id: int, request: Request):
 
 
 @router.get("/api/v2/workers/{worker_id}/runs")
-async def worker_runs(worker_id: int, request: Request):
+def worker_runs(worker_id: int, request: Request):
     _auth_user(request)
     limit, _offset = parse_pagination(request, default_limit=20)
     with get_conn() as conn:
@@ -199,7 +199,7 @@ async def worker_runs(worker_id: int, request: Request):
 
 
 @router.post("/api/v2/workers/{worker_id}/fork")
-async def fork_worker_endpoint(worker_id: int, request: Request):
+def fork_worker_endpoint(worker_id: int, request: Request):
     user = _auth_user(request, require_write=True)
     out = worker_service.fork_worker(worker_id, user["id"])
     audit_log(user, "worker.fork", "worker", worker_id, "", request)
@@ -207,7 +207,7 @@ async def fork_worker_endpoint(worker_id: int, request: Request):
 
 
 @router.get("/api/v2/workers-usage")
-async def workers_usage(request: Request):
+def workers_usage(request: Request):
     user = _auth_user(request)
     ws_raw = request.query_params.get("workspace_id")
     wid = int(ws_raw) if ws_raw and str(ws_raw).isdigit() else None