Phase 3.2 -- Agent Performance & Activity

Parent: #762

Context

The new dashboard shows agent biographies with performance metrics and activity timelines. The domain models exist (TaskMetricRecord, AgentLifecycleEvent, CollaborationScoreResult) but are not exposed via API.

Scope

GET /api/v1/agents/{agent_name}/performance

• Response: tasks_completed (total/7d/30d), avg_completion_time_seconds, success_rate_percent, cost_per_task_usd, quality_score, collaboration_score, trend_direction
• Data sources: TaskMetricRecord, CollaborationScoreResult from PerformanceTracker

GET /api/v1/agents/{agent_name}/activity (paginated)

• Response: paginated list of {event_type, timestamp, description, related_ids}
• Event types: hired, fired, promoted, demoted, task_started, task_completed, tool_used, delegation_sent, delegation_received, cost_incurred
• Data sources: AgentLifecycleEvent + inferred events from TaskMetricRecord

GET /api/v1/agents/{agent_name}/history

• Response: career events (hire date, role changes, promotions, milestones)
• Data source: AgentLifecycleEvent (already persisted via LifecycleEventRepository)

Deliverables

• Performance metrics endpoint
• Paginated activity timeline endpoint
• Career history endpoint
• Unit tests
• OpenAPI schema updated