Add standalone proxy management:
- Multi-step validation pipeline (DNS, TCP, HTTP) with diagnostic hints
- Proxy lifecycle: create/update/delete via NPM API with SSL auto-assign
- Periodic health monitoring (5min) with event log on status transitions
- Unified /api/proxies/all endpoint merging standalone + managed proxies
- Frontend types and API functions for downstream UI phases
alexei.dolgolyov
7a85441b81