feat(analytics): add Agent usage analytics to admin panel
Add full-stack Agent execution tracking and analytics:
**Database (conversation-service)**
- New `agent_executions` table: tracks each specialist Agent invocation
with agentType, agentName, durationMs, success, tenantId
- Migration: AddAgentExecutionsTable1738800000000
- ORM entity: AgentExecutionORM with indexes on tenant, conversation,
agentType, createdAt, and (tenant+date) composite
**Data Capture (conversation-service)**
- conversation.service.ts: captures `agent_start` and `agent_complete`
StreamChunk events in the sendMessage() async generator loop
- Persists agent execution records to DB after each message completes
- Non-blocking: agent persistence failures are logged but don't break
the main conversation flow
**Admin API (conversation-service)**
- GET /conversations/admin/statistics/agents?days=30
Aggregated stats per agent type: totalCalls, successCount, failureCount,
successRate, avgDurationMs, min/max duration
- GET /conversations/admin/statistics/agents/trend?days=7&agentType=
Daily trend data: date, agentType, calls, avgDurationMs, successRate
- GET /conversations/admin/:id/agent-executions
Per-conversation agent execution records ordered by createdAt
**Admin Client - Analytics Page**
- New AgentAnalyticsTab component with:
- 4 summary cards (total calls, success rate, avg duration, top agent)
- Agent statistics table (Ant Design Table with sortable columns,
color-coded Tags, Progress bar for success rate)
- Stacked bar trend chart (Recharts BarChart, color per agent type)
- Time range selectors (7/14/30/90 days)
- Added as third tab "Agent 使用分析" in AnalyticsPage dimension tabs
**Admin Client - Conversations Page**
- Added "Agent 使用详情" section to conversation detail drawer
(between Token Usage and Messages sections)
- Shows per-conversation agent execution table with agent name (color Tag),
duration, success/failure status, and timestamp
- Empty state: "暂无 Agent 使用记录"
Agent color mapping: policy_expert=#1890ff, assessment_expert=#52c41a,
strategist=#722ed1, objection_handler=#eb2f96, case_analyst=#faad14,
memory_manager=#13c2c2
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
hailin
691a3523e8