feat(hub): 事件去重(A-4) + 审计写入路径(A-8)

A-4 FeishuEventReceipt:
- 新增 FeishuEventReceipt 表(eventId @unique),lark ws 至少一次投递的幂等兜底
- MessageReceiveEvent 加 header.event_id 字段
- trigger 入口查重:已存在的 event_id → 跳过(不建第二次 run)
- resetDb 加入 FeishuEventReceipt

A-8 审计写入:
- AuditEntry 加 projectId(权限拒绝/slash 命令等无 run 的审计点可定位)
- 新建 src/audit.ts:writeAudit(prisma, entry) best-effort 写入(吞错,不阻断 trigger)
- trigger 五个审计点:trigger.denied / trigger.role_denied / run.created / run.lock_race / run.finished / run.failed
- 新增 audit unit 测试(3) + trigger 集成测试(去重 + 审计,2)

59 tests 全过。

hub/prisma/schema.prisma

@@ -83,6 +83,7 @@ model Project {
   permissionGrants   PermissionGrant[]     @relation("projectGrants")
   permissionSettings PermissionSettings[] @relation("projectSettings")
   roleTriggerGrants  RoleTriggerGrant[]   @relation("projectRoleGrants")
+  auditEntries       AuditEntry[]         @relation("projectAudit")
 
   @@index([archivedAt])
 }
@@ -294,18 +295,39 @@ model RoleTriggerGrant {
 
 /// spec AuditEntry: minimal skeleton — one entry relates to a run. Event type,
 /// actor, timestamp, details are OPEN. This table mirrors that: `runId` is the
-/// PINNED relation; the rest is open-shaped columns.
 model AuditEntry {
   id          String   @id @default(cuid())
   runId       String?
+  projectId   String?
   actorUserId String?
   action      String
   metadata    Json
   createdAt   DateTime @default(now())
 
-  actor User? @relation("auditActor", fields: [actorUserId], references: [id], onDelete: SetNull)
+  actor   User?    @relation("auditActor", fields: [actorUserId], references: [id], onDelete: SetNull)
+  project Project? @relation("projectAudit", fields: [projectId], references: [id], onDelete: SetNull)
 
   @@index([runId])
+  @@index([projectId, createdAt])
   @@index([actorUserId])
   @@index([createdAt])
 }
+
+// --- Feishu event dedup --------------------------------------------------
+
+/// Idempotency receipt for inbound Feishu ws events. The lark ws client may
+/// redeliver an event (at-least-once); without dedup a duplicate would spawn a
+/// second AgentRun — the lock would refuse it, but a FAILED run row + a busy
+/// reply would still leak. `eventId @unique` makes the second insert a no-op
+/// signal: the handler checks existence before processing.
+model FeishuEventReceipt {
+  id         String   @id @default(cuid())
+  eventId    String   @unique
+  eventType  String
+  messageId  String?
+  receivedAt DateTime @default(now())
+
+  @@index([eventType])
+  @@index([messageId])
+  @@index([receivedAt])
+}