feat: add proper Pydantic response_model to all stats endpoints

- Create comprehensive stats schemas in models/schema/stats.py:
  - ImportStatsResponse, UserStatsResponse, ProductStatsResponse
  - PlatformStatsResponse, AdminDashboardResponse
  - VendorDashboardStatsResponse with nested models
  - VendorAnalyticsResponse, CodeQualityDashboardStatsResponse
- Move DashboardStatsResponse from code_quality.py to schema file
- Fix get_vendor_statistics() to return pending_vendors field
- Fix get_vendor_stats() to return flat structure matching schema
- Add response_model to all stats endpoints:
  - GET /admin/dashboard -> AdminDashboardResponse
  - GET /admin/dashboard/stats/platform -> PlatformStatsResponse
  - GET /admin/marketplace-import-jobs/stats -> ImportStatsResponse
  - GET /vendor/dashboard/stats -> VendorDashboardStatsResponse
  - GET /vendor/analytics -> VendorAnalyticsResponse
- Enhance API-001 architecture rule with detailed guidance
- Add SVC-007 rule for service/schema compatibility

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/api/v1/vendor/analytics.py

@@ -15,16 +15,32 @@ from app.api.deps import get_current_vendor_api
 from app.core.database import get_db
 from app.services.stats_service import stats_service
 from models.database.user import User
+from models.schema.stats import (
+    VendorAnalyticsCatalog,
+    VendorAnalyticsImports,
+    VendorAnalyticsInventory,
+    VendorAnalyticsResponse,
+)
 
 router = APIRouter(prefix="/analytics")
 logger = logging.getLogger(__name__)
 
 
-@router.get("")
+@router.get("", response_model=VendorAnalyticsResponse)
 def get_vendor_analytics(
     period: str = Query("30d", description="Time period: 7d, 30d, 90d, 1y"),
     current_user: User = Depends(get_current_vendor_api),
     db: Session = Depends(get_db),
 ):
     """Get vendor analytics data for specified time period."""
-    return stats_service.get_vendor_analytics(db, current_user.token_vendor_id, period)
+    data = stats_service.get_vendor_analytics(db, current_user.token_vendor_id, period)
+
+    return VendorAnalyticsResponse(
+        period=data["period"],
+        start_date=data["start_date"],
+        imports=VendorAnalyticsImports(count=data["imports"]["count"]),
+        catalog=VendorAnalyticsCatalog(products_added=data["catalog"]["products_added"]),
+        inventory=VendorAnalyticsInventory(
+            total_locations=data["inventory"]["total_locations"]
+        ),
+    )