refactor: complete module-driven architecture migration

This commit completes the migration to a fully module-driven architecture:

## Models Migration
- Moved all domain models from models/database/ to their respective modules:
  - tenancy: User, Admin, Vendor, Company, Platform, VendorDomain, etc.
  - cms: MediaFile, VendorTheme
  - messaging: Email, VendorEmailSettings, VendorEmailTemplate
  - core: AdminMenuConfig
- models/database/ now only contains Base and TimestampMixin (infrastructure)

## Schemas Migration
- Moved all domain schemas from models/schema/ to their respective modules:
  - tenancy: company, vendor, admin, team, vendor_domain
  - cms: media, image, vendor_theme
  - messaging: email
- models/schema/ now only contains base.py and auth.py (infrastructure)

## Routes Migration
- Moved admin routes from app/api/v1/admin/ to modules:
  - menu_config.py -> core module
  - modules.py -> tenancy module
  - module_config.py -> tenancy module
- app/api/v1/admin/ now only aggregates auto-discovered module routes

## Menu System
- Implemented module-driven menu system with MenuDiscoveryService
- Extended FrontendType enum: PLATFORM, ADMIN, VENDOR, STOREFRONT
- Added MenuItemDefinition and MenuSectionDefinition dataclasses
- Each module now defines its own menu items in definition.py
- MenuService integrates with MenuDiscoveryService for template rendering

## Documentation
- Updated docs/architecture/models-structure.md
- Updated docs/architecture/menu-management.md
- Updated architecture validation rules for new exceptions

## Architecture Validation
- Updated MOD-019 rule to allow base.py in models/schema/
- Created core module exceptions.py and schemas/ directory
- All validation errors resolved (only warnings remain)

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

app/modules/tenancy/services/vendor_service.py

@@ -25,10 +25,10 @@ from app.modules.tenancy.exceptions import (
 )
 from app.modules.marketplace.models import MarketplaceProduct
 from app.modules.catalog.models import Product
-from models.database.user import User
-from models.database.vendor import Vendor
+from app.modules.tenancy.models import User
+from app.modules.tenancy.models import Vendor
 from app.modules.catalog.schemas import ProductCreate
-from models.schema.vendor import VendorCreate
+from app.modules.tenancy.schemas.vendor import VendorCreate
 
 logger = logging.getLogger(__name__)
 
@@ -63,7 +63,7 @@ class VendorService:
             UnauthorizedVendorAccessException: If user is not company owner
             InvalidVendorDataException: If vendor data is invalid
         """
-        from models.database.company import Company
+        from app.modules.tenancy.models import Company
 
         try:
             # Validate company_id is provided
@@ -159,7 +159,7 @@ class VendorService:
             # Non-admin users can only see active and verified vendors, plus their own
             if current_user.role != "admin":
                 # Get vendor IDs the user owns through companies
-                from models.database.company import Company
+                from app.modules.tenancy.models import Company
 
                 owned_vendor_ids = (
                     db.query(Vendor.id)
@@ -243,7 +243,7 @@ class VendorService:
         """
         from sqlalchemy.orm import joinedload
 
-        from models.database.company import Company
+        from app.modules.tenancy.models import Company
 
         vendor = (
             db.query(Vendor)
@@ -291,7 +291,7 @@ class VendorService:
         """
         from sqlalchemy.orm import joinedload
 
-        from models.database.company import Company
+        from app.modules.tenancy.models import Company
 
         vendor = (
             db.query(Vendor)
@@ -325,7 +325,7 @@ class VendorService:
         """
         from sqlalchemy.orm import joinedload
 
-        from models.database.company import Company
+        from app.modules.tenancy.models import Company
 
         # Try as integer ID first
         try: