feat(core): sync production orchestrator implementation from may-thang node

- add 22-state FSM state machine (src/domain/state.mjs)
- add comprehensive orchestrator business logic (src/orchestrator.mjs)
- add domain services (pricing, booking slot hold, catalog, handoff)
- add persistence layer and sql migration
- add 7 automated unit and lifecycle tests (100% pass)
- update documentation and architecture specification
