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/brain/README.md

@@ -13,11 +13,13 @@ A Clawdbot skill for integrating with Mosaic Stack's Ideas/Brain API.
 ## Installation
 
 1. Copy this skill to your Clawdbot skills directory or link it:
+
    ```bash
    ln -s ~/src/mosaic-stack/packages/skills/brain ~/.config/clawdbot/skills/mosaic-brain
    ```
 
 2. Configure your Mosaic Stack connection:
+
    ```bash
    mkdir -p ~/.config/mosaic
    cat > ~/.config/mosaic/brain.conf <<EOF

packages/skills/brain/SKILL.md

@@ -2,7 +2,7 @@
 name: mosaic-brain
 description: Capture ideas, brain dumps, and semantic search across your Mosaic Stack knowledge base.
 homepage: https://mosaicstack.dev
-metadata: {"clawdbot":{"emoji":"🧠","requires":{"bins":["curl","jq"]}}}
+metadata: { "clawdbot": { "emoji": "🧠", "requires": { "bins": ["curl", "jq"] } } }
 ---
 
 # Mosaic Brain
@@ -13,6 +13,7 @@ Capture and search ideas, brain dumps, and notes in your Mosaic Stack workspace.
 
 1. Ensure Mosaic Stack API is running (default: `http://localhost:3001`)
 2. Set environment variables:
+
    ```bash
    export MOSAIC_API_URL="http://localhost:3001"
    export MOSAIC_WORKSPACE_ID="your-workspace-uuid"
@@ -29,7 +30,9 @@ Capture and search ideas, brain dumps, and notes in your Mosaic Stack workspace.
 ## Common Commands
 
 ### Quick Brain Dump
+
 Capture an idea quickly without thinking about categorization:
+
 ```bash
 # Quick capture
 ./brain.sh capture "Had a great idea about using AI for code reviews"
@@ -39,7 +42,9 @@ Capture an idea quickly without thinking about categorization:
 ```
 
 ### Create Detailed Idea
+
 Create an idea with full metadata:
+
 ```bash
 ./brain.sh create \
   --title "New Feature Idea" \
@@ -49,7 +54,9 @@ Create an idea with full metadata:
 ```
 
 ### Semantic Search
+
 Search your brain using natural language:
+
 ```bash
 # Query your knowledge base
 ./brain.sh query "What did I say about AI and code reviews?"
@@ -59,6 +66,7 @@ Search your brain using natural language:
 ```
 
 ### List Ideas
+
 ```bash
 # List recent ideas
 ./brain.sh list
@@ -68,11 +76,13 @@ Search your brain using natural language:
 ```
 
 ### Get Specific Idea
+
 ```bash
 ./brain.sh get <idea-id>
 ```
 
 ### Update Idea
+
 ```bash
 ./brain.sh update <idea-id> \
   --title "Updated Title" \
@@ -81,11 +91,13 @@ Search your brain using natural language:
 ```
 
 ### Delete Idea
+
 ```bash
 ./brain.sh delete <idea-id>
 ```
 
 ### Tag Management
+
 ```bash
 # List all tags
 ./brain.sh tags
@@ -113,11 +125,13 @@ The skill uses these Mosaic Stack API endpoints:
 ## Configuration
 
 Config file priority:
+
 1. Environment variables
 2. `~/.config/mosaic/brain.conf`
 3. Default values
 
 Required settings:
+
 - `MOSAIC_API_URL` - API base URL (default: http://localhost:3001)
 - `MOSAIC_WORKSPACE_ID` - Your workspace UUID
 - `MOSAIC_API_TOKEN` - Authentication token
@@ -125,6 +139,7 @@ Required settings:
 ## Usage from Clawdbot
 
 Natural language examples:
+
 - "Remember this..." / "Note to self..." → Quick capture
 - "What did I say about..." → Semantic search
 - "Show me my recent ideas" → List ideas