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]>

apps/web/app/api/feeds.ts

@@ -72,14 +72,16 @@ export function useFetchFeedNow() {
 }
 
 /**
- * 疑似缺口:Feed 窗口与上次零重叠时服务端发 feed.gap_suspected 并排补漏。
- * 列表字段里没有显式标记,这里按 cursor 里的 gapSuspectedAt(若服务端写入)或"距上次成功超过 3 个周期"推断,并标"疑似"。
+ * 疑似缺口:服务端在 Feed 窗口与上次零重叠时写 possibleGap 并排站点补漏;下一次抓取衔接上后清空。
+ * 没有服务端标记但"距上次成功超过 3 个周期"时,只作推断提示(标"可能")。
  */
 export function feedGapHint(f: FeedSource, now = Date.now()): string | null {
-  const gapAt = typeof f.cursor.gapSuspectedAt === "string" ? f.cursor.gapSuspectedAt : null;
-  if (gapAt) return `疑似缺口(${new Date(gapAt).toLocaleString("zh-CN", { hour12: false })} 检测,已排补漏)`;
+  if (f.possibleGap) {
+    const at = new Date(f.possibleGap.detectedAt).toLocaleString("zh-CN", { hour12: false });
+    return `疑似缺口(${at} 检测,${f.possibleGap.backfillQueued ? "已排补漏" : "Feed 未关联站点,无法自动补漏"})`;
+  }
   if (!f.enabled || !f.lastSuccessAt) return null;
   const gapMs = now - new Date(f.lastSuccessAt).getTime();
-  if (gapMs > f.pollIntervalSec * 1000 * 3) return "距上次成功已超过 3 个周期,可能漏项(疑似)";
+  if (gapMs > f.pollIntervalSec * 1000 * 3) return "距上次成功已超过 3 个周期,可能漏项";
   return null;
 }