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/models/media.py

@@ -0,0 +1,124 @@
+# app/modules/cms/models/media.py
+"""
+CORE media file model for vendor media library.
+
+This is a CORE framework model used across multiple modules.
+MediaFile provides vendor-uploaded media files (images, documents, videos).
+
+For product-media associations, use:
+    from app.modules.catalog.models import ProductMedia
+
+Files are stored in vendor-specific directories:
+  uploads/vendors/{vendor_id}/{folder}/{filename}
+"""
+
+from sqlalchemy import (
+    Boolean,
+    Column,
+    ForeignKey,
+    Index,
+    Integer,
+    String,
+    Text,
+)
+from sqlalchemy.dialects.sqlite import JSON
+from sqlalchemy.orm import relationship
+
+from app.core.database import Base
+from models.database.base import TimestampMixin
+
+
+class MediaFile(Base, TimestampMixin):
+    """Vendor media file record.
+
+    Stores metadata about uploaded files. Actual files are stored
+    in the filesystem at uploads/vendors/{vendor_id}/{folder}/
+    """
+
+    __tablename__ = "media_files"
+
+    id = Column(Integer, primary_key=True, index=True)
+    vendor_id = Column(Integer, ForeignKey("vendors.id"), nullable=False)
+
+    # File identification
+    filename = Column(String(255), nullable=False)  # Stored filename (UUID-based)
+    original_filename = Column(String(255))  # Original uploaded filename
+    file_path = Column(String(500), nullable=False)  # Relative path from uploads/
+
+    # File properties
+    media_type = Column(String(20), nullable=False)  # image, video, document
+    mime_type = Column(String(100))
+    file_size = Column(Integer)  # bytes
+
+    # Image/video dimensions
+    width = Column(Integer)
+    height = Column(Integer)
+
+    # Thumbnail (for images/videos)
+    thumbnail_path = Column(String(500))
+
+    # Metadata
+    alt_text = Column(String(500))
+    description = Column(Text)
+    folder = Column(String(100), default="general")  # products, general, etc.
+    tags = Column(JSON)  # List of tags for categorization
+    extra_metadata = Column(JSON)  # Additional metadata (EXIF, etc.)
+
+    # Status
+    is_optimized = Column(Boolean, default=False)
+    optimized_size = Column(Integer)  # Size after optimization
+
+    # Usage tracking
+    usage_count = Column(Integer, default=0)  # How many times used
+
+    # Relationships
+    vendor = relationship("Vendor", back_populates="media_files")
+    # ProductMedia relationship uses string reference to avoid circular import
+    product_associations = relationship(
+        "ProductMedia",
+        back_populates="media",
+        cascade="all, delete-orphan",
+    )
+
+    __table_args__ = (
+        Index("idx_media_vendor_id", "vendor_id"),
+        Index("idx_media_vendor_folder", "vendor_id", "folder"),
+        Index("idx_media_vendor_type", "vendor_id", "media_type"),
+        Index("idx_media_filename", "filename"),
+    )
+
+    def __repr__(self):
+        return (
+            f"<MediaFile(id={self.id}, vendor_id={self.vendor_id}, "
+            f"filename='{self.filename}', type='{self.media_type}')>"
+        )
+
+    @property
+    def file_url(self) -> str:
+        """Get the public URL for this file."""
+        return f"/uploads/{self.file_path}"
+
+    @property
+    def thumbnail_url(self) -> str | None:
+        """Get the thumbnail URL if available."""
+        if self.thumbnail_path:
+            return f"/uploads/{self.thumbnail_path}"
+        return None
+
+    @property
+    def is_image(self) -> bool:
+        """Check if this is an image file."""
+        return self.media_type == "image"
+
+    @property
+    def is_video(self) -> bool:
+        """Check if this is a video file."""
+        return self.media_type == "video"
+
+    @property
+    def is_document(self) -> bool:
+        """Check if this is a document file."""
+        return self.media_type == "document"
+
+
+__all__ = ["MediaFile"]