feat(dvr)!: unify live and VOD/series recording into one recoverable DVR
Merge fix/merge_live_and_vod_recording into develop.
- One recording queue for scheduled live captures and VOD/series transfers,
with a shared transition graph, provider-slot scheduling, resumable HTTP
transfers (strong ETag / Last-Modified validation) and ffmpeg live capture.
- Crash-recoverable persistence: B+Tree repository with a journal-first
recovery history; one file can be shared by several library entries.
- Admission checks quota and disk on request, at transfer start (real size)
and before an entry attaches to a finished file; idempotent requests.
- REST is command-only; state reaches clients via owner-filtered WebSocket
snapshots.
- Deleting a recording removes the file once no entry holds it; removing an
entry keeps a finished file and cleans up orphaned partials.
- User ids derive from the configured username (web:/api:); the identity
registry is gone.
- Spanish locale added; ru/ar completed; locale parity test.
BREAKING CHANGE: `video.download` is now `video.recording` (nested
`recording` keys move up, `download_priority`/`recording_priority` become
`priority`); old configs fail to load with a migration hint.
BREAKING CHANGE: `/api/v1/file/download*` and `/file/record` are removed in
favour of `/api/v1/recording/*`.
BREAKING CHANGE: `download.*` and `recording.write` permissions are replaced
by `recording.read|create|manage|delete`; tokens from before the change must
re-authenticate.
BREAKING CHANGE: the old recording queue does not migrate; existing
`identity_registry.json` is ignored.
