docs(changelog): Phase 4 Step 5 — record dot_alfred v2 Phase 4 work

Append Phase 4 entry under [Unreleased]:
* Added: rescan_show v2 signature + new rescan_movie + PACK empty-
  episodes semantics + Settings.tmdb_cache_ttl_days + library-index
  anchor-mismatch warning
* Removed: v1 dot_alfred stack (bridge/repository/serializer/sidecar),
  abstract domain ports (TVShowRepository / MovieRepository),
  application/library/ package, two Phase-3 quarantine test files
* Internal: 1233 → 1237 passing, 10 → 8 skips; MediaWithTracks
  mixin parked for Phase 5

Phase 3 entries left intact (historically accurate at commit time).

CHANGELOG.md

@@ -15,6 +15,69 @@ callers).
 
 ## [Unreleased]
 
+### Added
+
+- **`.alfred` v2 — Phase 4: v2-shaped `rescan_show` + new
+  `rescan_movie` + index anchor-warning + `tmdb_cache_ttl_days`
+  setting.** Fourth and final structural phase of
+  `specs/dot_alfred_v2.md` on branch `refactor/dot-alfred-v2`. The TV
+  + movie rescan orchestrators now write v2 release aggregates
+  (`SeriesRelease` / `MovieRelease`) via the concrete v2
+  repositories; the library index keeps auto-healing from the new
+  sidecars on its next read (no TMDB call from rescan — that stays
+  Phase 5).
+  - **`rescan_show`** moves from `alfred/application/library/` to
+    `alfred/application/tv_shows/` (symmetry with the new
+    `alfred/application/movies/`). New signature:
+    `(show_root, *, tmdb_id: TmdbId, imdb_id: ImdbId | None = None,
+    series_repo, scanner, prober, kb) -> SeriesRelease`.
+  - **`rescan_movie`** (new — `alfred/application/movies/rescan.py`)
+    locates the main video via `find_video_file`, runs
+    `inspect_release` once, and writes the per-movie `.alfred`
+    sidecar. `added_at = datetime.now(UTC)` on every rescan (the
+    sidecar records reconciliation time, not filesystem mtime).
+    Raises `MovieRescanFailed` when no video is found in the folder.
+  - **PACK semantics in `rescan_show`**: a single-video + no-episode
+    season becomes `SeasonRelease(mode=PACK, folder=…, episodes=())`.
+    The slot map stays empty until the Phase 5 TMDB sync supplies
+    `episode_count` — no fabricated `EpisodeRange` lands in the
+    sidecar.
+- **`Settings.tmdb_cache_ttl_days: int = 14`** — placeholder for the
+  Phase 5 TTL policy on library-index entries (`fetched_at + TTL`
+  drives refresh decisions).
+- **Library-index anchor-mismatch warning** — both
+  `DotAlfredTVShowLibraryIndex` and `DotAlfredMovieLibraryIndex` now
+  cross-check each entry's `metadata.path` against the on-disk
+  folder layout right after a successful parse. Drift is logged as a
+  `WARNING` (one per missing folder, with `tmdb_id`); the heal path
+  stays silent by construction (it always synthesizes from real
+  folder names).
+
+### Removed
+
+- **v1 dot_alfred stack and its abstract domain ports.** Deleted
+  `alfred/infrastructure/persistence/dot_alfred/{bridge,repository,
+  serializer,sidecar}.py`, plus the
+  `alfred/domain/{tv_shows,movies}/repositories.py` ABCs
+  (`TVShowRepository` / `MovieRepository`) — zero callers after
+  Phase 4. `dot_alfred/__init__.py` is rewritten as a v2-only
+  re-export (four concrete repositories + `ShowFolderUnknown`).
+- **`alfred/application/library/` package** (rescan + walker moved
+  to `alfred/application/tv_shows/`).
+- The two Phase 3 module-level test skips
+  (`test_repository.py`, `test_serializer.py`) are lifted by
+  deleting the quarantined files.
+
+### Internal
+
+- **Suite**: 1233 → 1237 passing; 10 → 8 skips (only LLM-not-running
+  skips remain — the Phase 3 quarantines are gone with their files).
+- The `MediaWithTracks` mixin in `alfred.domain.shared.media` is
+  orphaned after Phase 3 (no aggregate inherits it). **Parked for
+  Phase 5**, which will either mount it on `MovieRelease` /
+  `SeasonRelease` (both already carry `audio_tracks` +
+  `subtitle_tracks`) or remove it for good.
+
 ### Changed
 
 - **`.alfred` v2 — Phase 3: `TVShow` / `Movie` aggregates become