fix: resolve cross-module import violations with lazy import pattern

- Convert core→optional imports to lazy imports with try/except fallbacks
- cms/media_service: use TYPE_CHECKING for ProductMedia type hints
- customers/customer_service: wrap Order imports in try/except
- tenancy/admin_platform_users: wrap stats_service import in try/except
- Enhance validate_architecture.py to recognize lazy import patterns
- Add module_dependency_graph.py script for dependency visualization

The lazy import pattern allows optional modules to be truly optional while
maintaining type safety through TYPE_CHECKING blocks.

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

app/modules/tenancy/routes/api/admin_platform_users.py

@@ -15,7 +15,6 @@ from sqlalchemy.orm import Session
 from app.api.deps import get_current_admin_api
 from app.core.database import get_db
 from app.modules.tenancy.services.admin_service import admin_service
-from app.modules.analytics.services.stats_service import stats_service
 from models.schema.auth import UserContext
 from models.schema.auth import (
     UserCreate,
@@ -111,7 +110,19 @@ def get_user_statistics(
     current_admin: UserContext = Depends(get_current_admin_api),
 ):
     """Get user statistics for admin dashboard (Admin only)."""
-    return stats_service.get_user_statistics(db)
+    try:
+        from app.modules.analytics.services.stats_service import stats_service
+
+        return stats_service.get_user_statistics(db)
+    except ImportError:
+        # Analytics module not available - return empty stats
+        logger.warning("Analytics module not available for user statistics")
+        return {
+            "total_users": 0,
+            "active_users": 0,
+            "inactive_users": 0,
+            "admin_users": 0,
+        }
 
 
 @admin_platform_users_router.get("/search", response_model=UserSearchResponse)