fix(system): retired heartbeat rows no longer alarm on status page

- GET /system/health splits processes into current instances (hosts with
  a beat in the last 10 min, newest per host+kind, not stopped) and
  retiredProcesses[]; 45s stale and level only consider current ones
- heartbeat writer marks stopped_at on graceful exit (migration 0043),
  upsert clears it; pure api role now stops its writer on SIGTERM
- scheduled job system.heartbeat_cleanup (maintain, 1h) deletes rows
  without a beat for 24h and samples older than 7 days
- status page: per-role alarms ("io worker 45 秒没有心跳"), collapsible
  retired instances; glossary/runbook updated
- bump all members to 0.2.2, CHANGELOG [0.2.2]

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

packages/db/src/index.ts

@@ -1,5 +1,5 @@
 // 统一从本包取 Kysely 与 sql,避免各包各装一份 kysely
-export { type Kysely, sql, type Transaction } from "kysely";
+export { type Kysely, type Selectable, sql, type Transaction } from "kysely";
 export {
   type CachedOptions,
   cachedCall,

packages/db/src/types.ts

@@ -1152,6 +1152,7 @@ export interface ProcessHeartbeatTable {
   concurrency: Generated<Json>;
   running_runs: number | null;
   extra: Generated<Json>;
+  stopped_at: Timestamptz | null;
 }
 
 export interface ProcessHeartbeatSampleTable {