feat(server): W4-A integration endpoints and contract gaps

- POST /acquisition-plans: manual submit via download.plan -> download.submit
  (same authorization/audit/idempotency path as the agent), slotId or entityId
- read-only /media-assets, /asset-locations, /asset-unit-coverage, /path-bindings,
  /reconcile-runs, /server-mappings, /artifacts, GET /title-aliases/{id};
  unimplemented write endpoints removed from api.ts; registry test now checks both directions
- candidate evaluation upsert per (slot, source_release) + migration 0022 dedupe/unique index
- organization records expose downloadTaskId (+ list filter); inventory adds
  subscribed/candidateReasons; feed sources expose derived possibleGap
- GET /events?after=&limit= JSON replay page for API key callers (same sse_event table)
- preference tag revision history from audit_event; subscriptions/identities/aliases
  lists carry mediaEntityTitle; subscription q/mediaKind search; slot subscriptionId
  filter + currentAsset summary; policy preview samples carry title/reasons
- DecisionSummary, IdentityRevisionList, ReleaseIdentityResult, PolicyPreviewSummary exported from contracts

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

packages/contracts/src/content.ts

@@ -113,6 +113,8 @@ export const TitleAlias = EntityBase.extend({
   kind: AliasKind,
   source: AliasSource,
   locked: z.boolean(),
+  /** 派生字段(列表返回):作品标题 */
+  mediaEntityTitle: z.string().nullable().optional(),
 });
 export type TitleAlias = z.infer<typeof TitleAlias>;
 /** normalized 由服务端计算,不接受客户端传入 */