feat(library): show stored versions per episode and movie (LIBV-1)

- domain versionSpecOf: file name + ffprobe + ingest quality -> version spec;
  summarizeVersions; matchVersions (satisfied / missing / upgradeable, single target)
- GET /library/{id}/versions: per-season/episode versions, summaries, matches[]
- organize writes full spec into media_asset.delivery (specVersion 1)
- scripts/asset-spec-backfill.ts: dry-run by default, --probe local only, --apply
- web: season summary line, one-line spec per episode, N versions expand,
  tech info details (TODO: DEAI-2 TechInfo), movie versions panel

Co-Authored-By: Claude Opus 5.5 <[email protected]>

packages/domain/src/index.ts

@@ -4,6 +4,7 @@ export const PACKAGE_NAME = "@umt/domain";
 export * from "./acquisition/index.ts";
 export * from "./download-state/index.ts";
 export * from "./identity/index.ts";
+export * from "./library/versions.ts";
 export * from "./naming/index.ts";
 export * from "./organize/index.ts";
 export * from "./path/index.ts";