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/web-ui-implementation.md

@@ -7,24 +7,28 @@ The Mosaic Stack web UI provides a PDA-friendly interface for managing tasks and
 ## Features
 
 ### Authentication
+
 - **Login Page:** Clean landing page with Authentik OIDC integration
 - **Session Management:** Automatic session refresh and validation
 - **Protected Routes:** Automatic redirect for unauthenticated users
 - **Logout:** Clean session termination
 
 ### Task Management
+
 - **Task List View:** Grouped by date (Today, Tomorrow, This Week, etc.)
 - **PDA-Friendly Language:** No demanding terms like "overdue" or "urgent"
 - **Status Indicators:** Visual emoji-based status (🟢 In Progress, ⚪ Not Started, etc.)
 - **Priority Badges:** Calm, non-aggressive priority display
 
 ### Calendar
+
 - **Event List View:** Chronological event display
 - **Time Display:** Clear start/end times with location
 - **Date Grouping:** Same grouping as tasks for consistency
 - **All-Day Events:** Proper handling of all-day events
 
 ### Navigation
+
 - **Fixed Header:** Always accessible navigation
 - **Active Route Highlighting:** Clear visual indication
 - **User Display:** Shows logged-in user name/email
@@ -33,10 +37,12 @@ The Mosaic Stack web UI provides a PDA-friendly interface for managing tasks and
 ## PDA-Friendly Design Principles
 
 ### Language
+
 - ❌ **Never Use:** OVERDUE, URGENT, CRITICAL, MUST DO, REQUIRED
 - ✅ **Always Use:** Target passed, Approaching target, High priority, Recommended
 
 ### Status Indicators
+
 - 🟢 In Progress / Active
 - 🔵 Not Started / Upcoming
 - ⏸️ Paused / On hold
@@ -45,6 +51,7 @@ The Mosaic Stack web UI provides a PDA-friendly interface for managing tasks and
 - ⚪ Default/Other
 
 ### Visual Design
+
 - **10-second scannability:** Key info immediately visible
 - **Visual chunking:** Clear sections with headers
 - **Single-line items:** Compact, scannable lists
@@ -90,11 +97,13 @@ apps/web/src/
 ## API Integration
 
 ### Authentication Endpoints
+
 - `GET /auth/session` - Get current session
 - `POST /auth/sign-out` - Logout
 - `GET /auth/callback/authentik` - OIDC callback
 
 ### Future Endpoints (Mock Data Ready)
+
 - `GET /api/tasks` - List tasks
 - `GET /api/events` - List events
 
@@ -127,12 +136,14 @@ pnpm test:coverage
 ## Testing
 
 ### Test Coverage
+
 - **API Client:** 100% coverage
 - **Auth Context:** Comprehensive tests
 - **Date Utilities:** All functions tested
 - **Components:** Tests for all major components
 
 ### Running Tests
+
 ```bash
 # All tests
 pnpm test
@@ -173,6 +184,7 @@ pnpm test:coverage
 ### For Developers
 
 **Adding a New Component:**
+
 1. Create component in appropriate directory
 2. Write tests FIRST (TDD)
 3. Implement component
@@ -180,6 +192,7 @@ pnpm test:coverage
 5. Export from index if needed
 
 **Connecting Real API:**
+
 ```typescript
 // Replace mock data with real API call
 import { useQuery } from "@tanstack/react-query";
@@ -192,6 +205,7 @@ const { data: tasks, isLoading } = useQuery({
 ```
 
 **Using Shared Types:**
+
 ```typescript
 import type { Task, Event, AuthUser } from "@mosaic/shared";
 import { TaskStatus, TaskPriority } from "@mosaic/shared";