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/scratchpads/3-prisma-orm-setup.md

@@ -1,9 +1,11 @@
 # Issue #3: Prisma ORM setup and migrations
 
 ## Objective
+
 Configure Prisma ORM for the mosaic-api backend with proper schema, migrations, seed scripts, and type generation.
 
 ## Requirements
+
 - [ ] Prisma schema matching PostgreSQL design
 - [ ] Prisma Client generation
 - [ ] Migration workflow (prisma migrate dev/deploy)
@@ -11,11 +13,13 @@ Configure Prisma ORM for the mosaic-api backend with proper schema, migrations,
 - [ ] Type generation for shared package
 
 ## Files
+
 - apps/api/prisma/schema.prisma
 - apps/api/prisma/seed.ts
 - apps/api/prisma/migrations/
 
 ## Progress
+
 - [x] Review existing Prisma schema
 - [x] Run code review
 - [x] Fix identified issues
@@ -23,6 +27,7 @@ Configure Prisma ORM for the mosaic-api backend with proper schema, migrations,
 - [x] Verify all tests pass
 
 ## Testing
+
 **All tests passing: 14/14 ✅**
 
 - PrismaService: 10 tests
@@ -40,11 +45,13 @@ Configure Prisma ORM for the mosaic-api backend with proper schema, migrations,
 ## Code Review Findings & Fixes
 
 ### Initial Issues Found:
+
 1. ❌ Missing unit tests for PrismaService
 2. ❌ Seed script not using transactions
 3. ❌ Seed script using N+1 pattern with individual creates
 
 ### Fixes Applied:
+
 1. ✅ Created comprehensive test suite (prisma.service.spec.ts)
 2. ✅ Wrapped seed operations in $transaction for atomicity
 3. ✅ Replaced loop with createMany for batch insertion
@@ -53,6 +60,7 @@ Configure Prisma ORM for the mosaic-api backend with proper schema, migrations,
 6. ✅ Added concurrency warning to seed script
 
 ### Final QA Results:
+
 - ✅ All code compiles successfully
 - ✅ All tests pass (14/14)
 - ✅ No security vulnerabilities
@@ -64,6 +72,7 @@ Configure Prisma ORM for the mosaic-api backend with proper schema, migrations,
 ## Notes
 
 ### Strengths:
+
 - Well-designed Prisma schema with proper indexes and relationships
 - Good use of UUID primary keys and timestamptz
 - Proper cascade delete relationships
@@ -71,6 +80,7 @@ Configure Prisma ORM for the mosaic-api backend with proper schema, migrations,
 - Comprehensive health check methods
 
 ### Technical Decisions:
+
 - Used Vitest for testing (project standard)
 - Transaction wrapper ensures atomic seed operations
 - Batch operations improve performance