feat(scheduler): add cron-style scheduled jobs (backend)

Adds a saved/named scheduling layer on top of Codeman's existing session
primitives. Distinct from the legacy run-now ScheduledRun concept.

- types/scheduler.ts: ScheduledJob + ScheduledJobRun
- state-store: persist scheduledJobs/scheduledJobRuns in ~/.codeman/state.json
- scheduler/scheduler-time.ts: pure once/interval/daily/weekly next-run math
- scheduler/scheduler-service.ts: CRUD, Run Now, due-checker tick, run history;
  reuses SessionPort (create -> start -> writeViaMux) for launches
- web/routes/scheduler-routes.ts: /api/scheduler/jobs CRUD + run + history
- web/schemas.ts: zod validation with schedule-type-aware refinements
- web/sse-events.ts: scheduler:* events
- server.ts: wire service into route context + 30s background tick loop
- test/scheduler-time.test.ts: 14 unit tests for next-run calculations

Phase 1 discovery recorded in SCHEDULER_DISCOVERY.md.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Rp7JhmQXcYJhmxFMdZuuah

src/web/sse-events.ts

@@ -240,6 +240,17 @@ export const ScheduledLog = 'scheduled:log' as const;
 /** Scheduled run deleted. */
 export const ScheduledDeleted = 'scheduled:deleted' as const;
 
+// ─── Scheduled Jobs (cron-style scheduler) ───────────────────────────────────
+
+/** The scheduled-jobs list changed (created/updated/enabled/run-status). Payload: { jobs }. */
+export const SchedulerJobsChanged = 'scheduler:jobsChanged' as const;
+/** A scheduled job was deleted. Payload: { id }. */
+export const SchedulerJobDeleted = 'scheduler:jobDeleted' as const;
+/** A scheduled-job run (history record) was created. Payload: ScheduledJobRun. */
+export const SchedulerRunCreated = 'scheduler:runCreated' as const;
+/** A scheduled-job run (history record) was updated. Payload: ScheduledJobRun. */
+export const SchedulerRunUpdated = 'scheduler:runUpdated' as const;
+
 // ─── Teams ───────────────────────────────────────────────────────────────────
 
 /** Agent team created. */
@@ -469,6 +480,12 @@ export const SseEvent = {
   ScheduledLog,
   ScheduledDeleted,
 
+  // Scheduled jobs (cron-style scheduler)
+  SchedulerJobsChanged,
+  SchedulerJobDeleted,
+  SchedulerRunCreated,
+  SchedulerRunUpdated,
+
   // Teams
   TeamCreated,
   TeamUpdated,