Send HTTP POST notifications to configured webhook URLs when batch
jobs complete or when scheduled analysis detects significant changes.
- Add SPARC/webhooks.py with retry logic (3 attempts, exponential backoff)
- Support generic HTTP POST and Slack-compatible text payloads
- Integrate into batch job completion handler in api.py
- Configure via WEBHOOK_URLS env var (comma-separated)
- Payload includes event type, job ID, status, and summary
Closesleeworks-agents/SPARC#23
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>