- Add `contract.go` to manage and validate embedded SQL migrations
- Introduce `AssertSchema` to verify database version at startup
- Include `SchemaMismatchError` with actionable recovery instructions
- Add comprehensive unit tests for version parsing and validation
- Add migrations for per-namespace publish sequences and persistent WebSocket function settings
- Integrate PersistentWSManager and WSBridge into the gateway dependency graph
- Upgrade serverless engine to use a multi-tier rate limiter
- Update JWT claims to support custom application-defined fields