scheduler: add per-section error handling in loadSchedules()

[ng]

Problem

Currently, if any single DB query fails in loadSchedules() (e.g., the alarmSchedules query), the entire load aborts. This leaves the scheduler in a partially initialized state where some job types are scheduled but others are missing, with no clear indication to the caller.

File: src/scheduler/jobManager.ts:70-111

Impact

• Development: Fail-fast behavior makes debugging easier
• Production: Single table failure could prevent ALL schedules from loading

Proposed Solution

Wrap each schedule type section in its own try/catch:

async loadSchedules(): Promise<void> {
  console.log('Loading schedules from database...')

  // Temperature schedules
  try {
    const tempSchedules = await db.select().from(temperatureSchedules)
    for (const sched of tempSchedules) {
      if (sched.enabled) {
        this.scheduleTemperature(sched)
      }
    }
  } catch (error) {
    console.error('Failed to load temperature schedules:', error)
  }

  // Repeat for power, alarm, and system schedules...
  
  console.log(`Loaded ${this.scheduler.getJobs().length} scheduled jobs`)
}

Priority

Medium - Should be implemented before production deployment for better resilience

References

• PR feat(scheduler): add job scheduling system with production-ready reliability fixes #111 - Job Scheduler Implementation
• CodeRabbit Review Comment (src/scheduler/jobManager.ts:70-111)
• Commit: 801872f (CodeRabbit review fixes)