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>