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/messaging/services/email_service.py

@@ -41,8 +41,8 @@ from jinja2 import Environment, BaseLoader
 from sqlalchemy.orm import Session
 
 from app.core.config import settings
-from models.database.email import EmailLog, EmailStatus, EmailTemplate
-from models.database.vendor_email_template import VendorEmailTemplate
+from app.modules.messaging.models import EmailLog, EmailStatus, EmailTemplate
+from app.modules.messaging.models import VendorEmailTemplate
 
 logger = logging.getLogger(__name__)
 
@@ -368,7 +368,7 @@ def get_platform_email_config(db: Session) -> dict:
     Returns:
         Dictionary with all email configuration values
     """
-    from models.database.admin import AdminSetting
+    from app.modules.tenancy.models import AdminSetting
 
     def get_db_setting(key: str) -> str | None:
         setting = db.query(AdminSetting).filter(AdminSetting.key == key).first()
@@ -1002,7 +1002,7 @@ class EmailService:
     def _get_vendor(self, vendor_id: int):
         """Get vendor with caching."""
         if vendor_id not in self._vendor_cache:
-            from models.database.vendor import Vendor
+            from app.modules.tenancy.models import Vendor
 
             self._vendor_cache[vendor_id] = (
                 self.db.query(Vendor).filter(Vendor.id == vendor_id).first()
@@ -1026,7 +1026,7 @@ class EmailService:
     def _get_vendor_email_settings(self, vendor_id: int):
         """Get vendor email settings with caching."""
         if vendor_id not in self._vendor_email_settings_cache:
-            from models.database.vendor_email_settings import VendorEmailSettings
+            from app.modules.messaging.models import VendorEmailSettings
 
             self._vendor_email_settings_cache[vendor_id] = (
                 self.db.query(VendorEmailSettings)