feat(analytics): add tabbed layout with coverage heatmap

Add Phase 5 types (CoverageResponse, FlowQualityResponse, EnhancedPsaMetrics)
and API methods. Refactor FlowPilotAnalyticsPage with tab bar (Overview,
Coverage, Flow Quality, PSA) with lazy data loading. Create CoverageHeatmap
component with color-coded resolution/escalation/guided rate cells.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/api/flowpilotAnalytics.ts

@@ -1,5 +1,5 @@
 import apiClient from './client'
-import type { FlowPilotDashboard, KnowledgeGapReport } from '@/types/flowpilot-analytics'
+import type { FlowPilotDashboard, KnowledgeGapReport, CoverageResponse, FlowQualityResponse, EnhancedPsaMetrics } from '@/types/flowpilot-analytics'
 
 export const flowpilotAnalyticsApi = {
   async getDashboard(period: string = '30d'): Promise<FlowPilotDashboard> {
@@ -15,6 +15,27 @@ export const flowpilotAnalyticsApi = {
     })
     return response.data
   },
+
+  async getCoverage(period: string = '30d'): Promise<CoverageResponse> {
+    const response = await apiClient.get<CoverageResponse>('/analytics/flowpilot/coverage', {
+      params: { period },
+    })
+    return response.data
+  },
+
+  async getFlowQuality(period: string = '30d', sort: string = 'quality'): Promise<FlowQualityResponse> {
+    const response = await apiClient.get<FlowQualityResponse>('/analytics/flowpilot/flow-quality', {
+      params: { period, sort },
+    })
+    return response.data
+  },
+
+  async getPsaMetrics(period: string = '30d'): Promise<EnhancedPsaMetrics> {
+    const response = await apiClient.get<EnhancedPsaMetrics>('/analytics/flowpilot/psa-metrics', {
+      params: { period },
+    })
+    return response.data
+  },
 }
 
 export default flowpilotAnalyticsApi