GenServer that polls for due scheduled workflows and triggers them.

This module runs as part of the Durable supervision tree and:

• Polls every 60 seconds for due schedules
• Uses FOR UPDATE SKIP LOCKED for multi-node safety
• Starts workflows via the normal queue system
• Updates last_run_at and next_run_at after each execution

Multi-Node Safety

When running multiple Durable instances (e.g., multiple app nodes), only one node will execute each scheduled workflow. This is achieved using PostgreSQL's FOR UPDATE SKIP LOCKED clause, which allows each node to atomically claim schedules without conflicts.

Configuration

The scheduler is automatically started when Durable starts. No additional configuration is required.