feat(analytics): add coverage heatmap and flow quality scoring endpoints

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

backend/app/schemas/flowpilot_analytics.py

@@ -54,6 +54,39 @@ class PsaMetrics(BaseModel):
     total_hours_logged: float
 
 
+class CoverageDomainRow(BaseModel):
+    domain: str
+    flow_count: int
+    session_count: int
+    resolution_rate: float
+    escalation_rate: float
+    guided_rate: float
+    avg_resolution_minutes: float | None = None
+
+
+class CoverageResponse(BaseModel):
+    domains: list[CoverageDomainRow]
+    unmapped_session_count: int
+    total_domains: int
+
+
+class FlowQualityRow(BaseModel):
+    flow_id: str
+    name: str
+    tree_type: str
+    usage_count: int
+    success_rate: float | None = None
+    last_matched_at: datetime | None = None
+    avg_confidence: float | None = None
+    quality_score: float
+
+
+class FlowQualityResponse(BaseModel):
+    flows: list[FlowQualityRow]
+    top_performers: list[FlowQualityRow]
+    needs_attention: list[FlowQualityRow]
+
+
 class FlowPilotDashboard(BaseModel):
     period: str
     total_sessions: int