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/README.md

@@ -13,13 +13,15 @@ Clawdbot skill for querying and analyzing project timelines, task dependencies,
 ## Installation
 
 1. **Copy skill to Clawdbot plugins directory:**
+
    ```bash
    cp -r ~/src/mosaic-stack-worktrees/feature-26-gantt-skill/packages/skills/gantt ~/.claude/plugins/mosaic-plugin-gantt
    ```
 
 2. **Set up environment variables:**
-   
+
    Add to your `.env` or shell profile:
+
    ```bash
    export MOSAIC_API_URL="http://localhost:3000"
    export MOSAIC_WORKSPACE_ID="your-workspace-uuid"
@@ -83,6 +85,7 @@ The `gantt-api.sh` helper script can be used directly:
 ### Authentication
 
 All requests require headers:
+
 - `X-Workspace-Id`: Workspace UUID
 - `Authorization`: Bearer {token}