Create automation(trees) version history

**Description:**
Track changes to automations with version control.

**Tasks:**
- [ ] Design version storage
- [ ] Auto-save versions
- [ ] Add version comparison
- [ ] Implement rollback
- [ ] Show version timeline
- [ ] Add commit messages
- [ ] Test with large histories

**Acceptance Criteria:**
- Versions saved automatically
- Comparison shows diffs
- Rollback works
- Timeline clear