[S6] Implement scheduled reconciliation (daily cron)

[krakenhavoc]

Description

BullMQ repeatable job that runs reconciliation for all active installations daily.

Implementation

• BullMQ repeatable job: cron 0 2 * * * (02:00 UTC daily)
• Job iterates all active installations → all active repo configs
• Enqueues individual reconciliation jobs for each repo config
• Stagger jobs (add random delay per job) to avoid GitHub API rate limit spikes

Rate Limit Management

• Track X-RateLimit-Remaining from GitHub API responses
• If remaining < 100, pause processing and wait until reset time
• Log rate limit warnings

Acceptance Criteria

• Cron job runs daily at 02:00 UTC
• All active repos are reconciled
• Rate limits are respected
• Staggered processing prevents burst API usage
• Certs expiring within threshold are renewed