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/cms/routes/api/admin_content_pages.py

@@ -23,7 +23,7 @@ from app.modules.cms.schemas import (
     SectionUpdateResponse,
 )
 from app.modules.cms.services import content_page_service
-from models.database.user import User
+from app.modules.tenancy.models import User
 
 admin_content_pages_router = APIRouter(prefix="/content-pages")
 logger = logging.getLogger(__name__)

app/modules/cms/routes/api/admin_images.py

@@ -15,7 +15,7 @@ from fastapi import APIRouter, Depends, File, Form, UploadFile
 from app.api.deps import get_current_admin_api
 from app.modules.core.services.image_service import image_service
 from models.schema.auth import UserContext
-from models.schema.image import (
+from app.modules.cms.schemas.image import (
     ImageDeleteResponse,
     ImageStorageStats,
     ImageUploadResponse,

app/modules/cms/routes/api/admin_media.py

@@ -14,7 +14,7 @@ from app.api.deps import get_current_admin_api
 from app.core.database import get_db
 from app.modules.cms.services.media_service import media_service
 from models.schema.auth import UserContext
-from models.schema.media import (
+from app.modules.cms.schemas.media import (
     MediaDetailResponse,
     MediaItemResponse,
     MediaListResponse,

app/modules/cms/routes/api/admin_vendor_themes.py

@@ -20,7 +20,7 @@ from sqlalchemy.orm import Session
 from app.api.deps import get_current_admin_api, get_db
 from app.modules.cms.services.vendor_theme_service import vendor_theme_service
 from models.schema.auth import UserContext
-from models.schema.vendor_theme import (
+from app.modules.cms.schemas.vendor_theme import (
     ThemeDeleteResponse,
     ThemePresetListResponse,
     ThemePresetResponse,

app/modules/cms/routes/api/vendor_content_pages.py

@@ -26,7 +26,7 @@ from app.modules.cms.schemas import (
 )
 from app.modules.cms.services import content_page_service
 from app.modules.tenancy.services.vendor_service import VendorService  # noqa: MOD-004 - shared platform service
-from models.database.user import User
+from app.modules.tenancy.models import User
 
 vendor_service = VendorService()
 

app/modules/cms/routes/api/vendor_media.py

@@ -16,7 +16,7 @@ from app.core.database import get_db
 from app.modules.cms.exceptions import MediaOptimizationException
 from app.modules.cms.services.media_service import media_service
 from models.schema.auth import UserContext
-from models.schema.media import (
+from app.modules.cms.schemas.media import (
     MediaDetailResponse,
     MediaItemResponse,
     MediaListResponse,