feat(#93): implement agent spawn via federation

Implements FED-010: Agent Spawn via Federation feature that enables
spawning and managing Claude agents on remote federated Mosaic Stack
instances via COMMAND message type.

Features:
- Federation agent command types (spawn, status, kill)
- FederationAgentService for handling agent operations
- Integration with orchestrator's agent spawner/lifecycle services
- API endpoints for spawning, querying status, and killing agents
- Full command routing through federation COMMAND infrastructure
- Comprehensive test coverage (12/12 tests passing)

Architecture:
- Hub → Spoke: Spawn agents on remote instances
- Command flow: FederationController → FederationAgentService →
  CommandService → Remote Orchestrator
- Response handling: Remote orchestrator returns agent status/results
- Security: Connection validation, signature verification

Files created:
- apps/api/src/federation/types/federation-agent.types.ts
- apps/api/src/federation/federation-agent.service.ts
- apps/api/src/federation/federation-agent.service.spec.ts

Files modified:
- apps/api/src/federation/command.service.ts (agent command routing)
- apps/api/src/federation/federation.controller.ts (agent endpoints)
- apps/api/src/federation/federation.module.ts (service registration)
- apps/orchestrator/src/api/agents/agents.controller.ts (status endpoint)
- apps/orchestrator/src/api/agents/agents.module.ts (lifecycle integration)

Testing:
- 12/12 tests passing for FederationAgentService
- All command service tests passing
- TypeScript compilation successful
- Linting passed

Refs #93

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

docs/1-getting-started/1-quick-start/1-overview.md

@@ -42,11 +42,11 @@ docker compose logs -f api
 
 ## What's Running?
 
-| Service | Port | Purpose |
-|---------|------|---------|
-| API | 3001 | NestJS backend |
-| PostgreSQL | 5432 | Database |
-| Valkey | 6379 | Cache (Redis-compatible) |
+| Service    | Port | Purpose                  |
+| ---------- | ---- | ------------------------ |
+| API        | 3001 | NestJS backend           |
+| PostgreSQL | 5432 | Database                 |
+| Valkey     | 6379 | Cache (Redis-compatible) |
 
 ## Next Steps
 
@@ -57,6 +57,7 @@ docker compose logs -f api
 ## Troubleshooting
 
 **Port already in use:**
+
 ```bash
 # Stop existing services
 docker compose down
@@ -66,6 +67,7 @@ lsof -i :3001
 ```
 
 **Database connection failed:**
+
 ```bash
 # Check PostgreSQL is running
 docker compose ps postgres