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>

packages/skills/gantt/SKILL.md

@@ -9,6 +9,7 @@ This skill enables querying project timelines, task dependencies, critical path
 ## Overview
 
 The Mosaic Stack provides project management capabilities with support for:
+
 - Project timelines with start/end dates
 - Task dependencies and scheduling
 - Task status tracking (NOT_STARTED, IN_PROGRESS, PAUSED, COMPLETED, ARCHIVED)
@@ -20,43 +21,51 @@ The Mosaic Stack provides project management capabilities with support for:
 **Base URL**: Configured via `MOSAIC_API_URL` environment variable (default: `http://localhost:3000`)
 
 ### Projects
+
 - `GET /projects` - List all projects with pagination
 - `GET /projects/:id` - Get project details with tasks
 
 ### Tasks
+
 - `GET /tasks` - List all tasks with optional filters
   - Query params: `projectId`, `status`, `priority`, `assigneeId`, `page`, `limit`
 
 ## Authentication
 
 Requests require authentication headers:
+
 - `X-Workspace-Id`: Workspace UUID (from `MOSAIC_WORKSPACE_ID` env var)
 - `Authorization`: Bearer token (from `MOSAIC_API_TOKEN` env var)
 
 ## Trigger Phrases & Examples
 
 **Query project timeline:**
+
 - "Show me the timeline for [project name]"
 - "What's the status of [project]?"
 - "Give me an overview of Project Alpha"
 
 **Check task dependencies:**
+
 - "What blocks task [task name]?"
 - "What are the dependencies for [task]?"
 - "Show me what's blocking [task]"
 
 **Project status overview:**
+
 - "Project status for [project]"
 - "How is [project] doing?"
 - "Summary of [project]"
 
 **Identify critical path:**
+
 - "Find the critical path for [project]"
 - "What's the critical path?"
 - "Show me blockers for [project]"
 - "Which tasks can't be delayed in [project]?"
 
 **Find upcoming deadlines:**
+
 - "What tasks are due soon in [project]?"
 - "Show me tasks approaching deadline"
 - "What's due this week?"
@@ -64,6 +73,7 @@ Requests require authentication headers:
 ## Data Models
 
 ### Project
+
 ```typescript
 {
   id: string;
@@ -79,6 +89,7 @@ Requests require authentication headers:
 ```
 
 ### Task
+
 ```typescript
 {
   id: string;
@@ -122,6 +133,7 @@ Use `gantt-api.sh` for API queries:
 ## PDA-Friendly Language
 
 When presenting information, use supportive, non-judgmental language:
+
 - **"Target passed"** instead of "OVERDUE" or "LATE"
 - **"Approaching target"** for near-deadline tasks
 - **"Paused"** not "BLOCKED" or "STUCK"