feat: enhance automation engine with fault edges, step logging, timeout, cycle detection, safe eval, parallel execution, versioning, and backoff

- Add backoffMultiplier, maxRetryDelayMs, jitter to FlowSchema.errorHandling
- Add timeoutMs, inputSchema, outputSchema to FlowNodeSchema
- Add FlowVersionHistorySchema for flow version management
- Implement fault edge error path support in DAG executor
- Add node step-level execution logging with timing
- Implement retry with exponential backoff, jitter, and recursive protection
- Add parallel branch execution (Promise.all for unconditional edges)
- Add node timeout mechanism (Promise.race)
- Implement DAG cycle detection on registerFlow
- Replace new Function with safe expression evaluator
- Add node input/output schema validation
- Add flow version history management and rollback

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>

Author: Copilot