feat(db,contracts): W5-C subscription units migration 0025, contracts and mapping

- subscription: status pending (TMDB not ready: searchable/evaluable, not completable),
  last_searched_at / next_search_at
- content_unit (season): episode_total ledger with source / lock / timestamp
- acquisition_plan: unit_keys (Slot × unit reservation) and file_selection; drop the
  one-in-flight-per-slot unique index (checked under slot row lock per unit instead)
- new tables slot_deferral, slot_unit (per-unit quality ledger), subscription_history
- contracts: SubscriptionParams, SubscriptionHistory, SlotDeferral, SlotUnit, SubscriptionProgress,
  EpisodeTotalSet, CandidateEvaluation pri/trace/unitKeys and decision deferred;
  endpoints subscriptions.search/progress/setEpisodeTotal and subscription-history
- mapping: evaluation messages via describeViolation, pri/trace passthrough

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

packages/contracts/src/content.ts

@@ -59,6 +59,10 @@ export type Segment = z.infer<typeof Segment>;
 export const ContentUnitStatus = z.enum(["provisional", "confirmed", "retired"]);
 export type ContentUnitStatus = z.infer<typeof ContentUnitStatus>;
 
+/** 季总集数来源:tmdb 元数据 / 插件注入(只升)/ 人工锁定 / 回退被已覆盖最高集兜住 / 沿用 */
+export const EpisodeTotalSource = z.enum(["tmdb", "injected", "manual", "covered_floor", "previous"]);
+export type EpisodeTotalSource = z.infer<typeof EpisodeTotalSource>;
+
 export const ContentUnit = EntityBase.extend({
   mediaEntityId: Id,
   parentUnitId: Id.nullable(),
@@ -77,6 +81,12 @@ export const ContentUnit = EntityBase.extend({
   numberingLocked: z.boolean(),
   metadata: JsonObject,
   fieldLocks: z.array(z.string()),
+  /** 季单元的总集数账本(只升;回退不低于已覆盖最高集);null = 未知,追更不结束 */
+  episodeTotal: z.number().int().nonnegative().nullable(),
+  episodeTotalSource: EpisodeTotalSource.nullable(),
+  /** 人工锁定总集数:元数据刷新与注入不再改写 */
+  episodeTotalLocked: z.boolean(),
+  episodeTotalAt: Timestamp.nullable(),
 });
 export type ContentUnit = z.infer<typeof ContentUnit>;
 export const ContentUnitCreate = ContentUnit.omit(SERVER_MANAGED).partial({
@@ -93,6 +103,10 @@ export const ContentUnitCreate = ContentUnit.omit(SERVER_MANAGED).partial({
   numberingLocked: true,
   metadata: true,
   fieldLocks: true,
+  episodeTotal: true,
+  episodeTotalSource: true,
+  episodeTotalLocked: true,
+  episodeTotalAt: true,
 });
 export type ContentUnitCreate = z.infer<typeof ContentUnitCreate>;
 export const ContentUnitUpdate = ContentUnitCreate.omit({ mediaEntityId: true }).partial();