storage: multi-storage management with per-storage quota

Replace the single fixed /records path with a list of storages and an
active selection (where new recordings go). Quota is now per-storage.

- config: StorageItem(id,name,type,path,quota_gb,nas-meta) + Storage keeps
  global retention_days/segment_seconds; active + items. Migration from the
  old single {path,quota_gb} schema → one local item.
- recorder: write to the active storage; restart_all() repoints on switch;
  NAS-not-mounted guard (never write into the container overlay).
- indexer: scan ALL storage roots so recordings survive an active switch.
- retention: enforce quota PER storage via db.total_size_under /
  oldest_recordings_under (path-prefix LIKE).
- api/storages: GET/POST/PUT/DELETE + activate + policy. NAS uses host-mount
  (backend stores SMB params, generates the mount/fstab command, reports
  ismount status). Retire old POST /api/storage.
- frontend: new "Хранилища" settings tab — table with inline per-row quota,
  add form (local folder / NAS SMB), global policy (segment + retention).
- compose: add shared ./storages:/storages root for extra local folders and
  host-mounted NAS shares.

VERSION 0.0.127.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

backend/app/api/system.py

@@ -3,16 +3,13 @@ from __future__ import annotations
 
 import os
 
-from fastapi import APIRouter, HTTPException, Request
+from fastapi import APIRouter
 
-from ..auth import require_role
-from ..config import Storage, save_config
 from ..runtime import runtime
 from ..services.system import system_stats
 
 router = APIRouter(prefix="/api", tags=["system"])
 
-ALLOWED_SEGMENTS = (60, 120, 300, 600, 900)   # 1 / 2 / 5 / 10 / 15 минут
 VERSION_FILE = os.environ.get("NVR_VERSION_FILE", "/app/VERSION")
 
 
@@ -36,25 +33,3 @@ async def get_system() -> dict:
 @router.get("/health")
 async def health() -> dict:
     return {"status": "ok"}
-
-
-@router.post("/storage")
-async def update_storage(request: Request) -> dict:
-    """Смена размера сегмента записи (1/5/10/15 мин). Перезапускает рекордеры."""
-    require_role(request, "admin")
-    body = await request.json()
-    try:
-        seg = int(body.get("segment_seconds"))
-    except (TypeError, ValueError):
-        raise HTTPException(400, "segment_seconds должен быть числом")
-    if seg not in ALLOWED_SEGMENTS:
-        raise HTTPException(400, "допустимо 60 / 300 / 600 / 900 секунд")
-
-    st = runtime.config.storage
-    runtime.config.storage = Storage(
-        path=st.path, quota_gb=st.quota_gb,
-        retention_days=st.retention_days, segment_seconds=seg,
-    )
-    save_config(runtime.config)
-    await runtime.supervisor.restart_all()
-    return {"segment_seconds": seg}