fix(quick-260610-i4x-01): replace node-cron schedule() with setInterval in three broker workers

- poller.ts: setInterval(cb, 5 * 60 * 1000) replaces schedule('*/5 * * * *', cb)
- outboxWorker.ts: setInterval(cb, 15 * 1000) replaces schedule('*/15 * * * * *', cb)
- reminderScheduler.ts: setInterval(cb, 60 * 1000) replaces schedule('* * * * *', cb)
- Remove 'import { schedule } from node-cron' from all three files
- Update doc comments to reflect setInterval and document why (node-cron 4.2.1 silent skip)
- Callback bodies and .catch wrappers unchanged; typecheck clean; 91/91 broker tests pass

apps/api/src/broker/poller.ts

@@ -1,5 +1,5 @@
 /**
- * CalDAV broker poller — runs every 5 minutes via node-cron.
+ * CalDAV broker poller — runs every 5 minutes via setInterval.
  *
  * Responsibilities (D-13, D-02):
  *   - Load all member_credentials (N-credential per-member model)
@@ -10,12 +10,10 @@
  *       → ctag changed or null: call syncCalendar (REPORT → ical.js → DB upsert)
  *
  * runPoll is exported for unit testing (inject mocks via vi.mock at the module level).
- * startBrokerPoller wraps it in node-cron's 5-minute schedule.
- *
- * Source: https://github.com/node-cron/node-cron (v4 stable basic API)
+ * startBrokerPoller wraps it in a 5-minute setInterval.
+ * (node-cron 4.2.1 silently skipped scheduled executions in the long-running server process;
+ * setInterval fires reliably in the same process — replaced to fix the silent skip.)
  */
-
-import { schedule } from 'node-cron'
 import { and, eq } from 'drizzle-orm'
 import { db } from '../db/client.js'
 import { memberCredentials, calendars } from '../db/schema.js'
@@ -91,11 +89,13 @@ export async function runPoll(): Promise<void> {
 /**
  * Starts the 5-minute background polling schedule.
  * Call once at API startup (Plan 04 wires this into index.ts).
+ * Uses setInterval instead of node-cron: node-cron 4.2.1 silently skipped executions
+ * in the long-running server process; setInterval fires reliably.
  */
 export function startBrokerPoller(): void {
-  schedule('*/5 * * * *', () => {
+  setInterval(() => {
     runPoll().catch((err: unknown) => {
       console.error('[broker/poller] Unhandled runPoll error:', err)
     })
-  })
+  }, 5 * 60 * 1000)
 }