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/schemas/vendor_theme.py

@@ -0,0 +1,108 @@
+# app/modules/cms/schemas/vendor_theme.py
+"""
+Pydantic schemas for vendor theme operations.
+"""
+
+from pydantic import BaseModel, Field
+
+
+class VendorThemeColors(BaseModel):
+    """Color scheme for vendor theme."""
+
+    primary: str | None = Field(None, description="Primary brand color")
+    secondary: str | None = Field(None, description="Secondary color")
+    accent: str | None = Field(None, description="Accent/CTA color")
+    background: str | None = Field(None, description="Background color")
+    text: str | None = Field(None, description="Text color")
+    border: str | None = Field(None, description="Border color")
+
+
+class VendorThemeFonts(BaseModel):
+    """Typography settings for vendor theme."""
+
+    heading: str | None = Field(None, description="Font for headings")
+    body: str | None = Field(None, description="Font for body text")
+
+
+class VendorThemeBranding(BaseModel):
+    """Branding assets for vendor theme."""
+
+    logo: str | None = Field(None, description="Logo URL")
+    logo_dark: str | None = Field(None, description="Dark mode logo URL")
+    favicon: str | None = Field(None, description="Favicon URL")
+    banner: str | None = Field(None, description="Banner image URL")
+
+
+class VendorThemeLayout(BaseModel):
+    """Layout settings for vendor theme."""
+
+    style: str | None = Field(
+        None, description="Product layout style (grid, list, masonry)"
+    )
+    header: str | None = Field(
+        None, description="Header style (fixed, static, transparent)"
+    )
+    product_card: str | None = Field(
+        None, description="Product card style (modern, classic, minimal)"
+    )
+
+
+class VendorThemeUpdate(BaseModel):
+    """Schema for updating vendor theme (partial updates allowed)."""
+
+    theme_name: str | None = Field(None, description="Theme preset name")
+    colors: dict[str, str] | None = Field(None, description="Color scheme")
+    fonts: dict[str, str] | None = Field(None, description="Font settings")
+    branding: dict[str, str | None] | None = Field(None, description="Branding assets")
+    layout: dict[str, str] | None = Field(None, description="Layout settings")
+    custom_css: str | None = Field(None, description="Custom CSS rules")
+    social_links: dict[str, str] | None = Field(None, description="Social media links")
+
+
+class VendorThemeResponse(BaseModel):
+    """Schema for vendor theme response."""
+
+    theme_name: str = Field(..., description="Theme name")
+    colors: dict[str, str] = Field(..., description="Color scheme")
+    fonts: dict[str, str] = Field(..., description="Font settings")
+    branding: dict[str, str | None] = Field(..., description="Branding assets")
+    layout: dict[str, str] = Field(..., description="Layout settings")
+    social_links: dict[str, str] | None = Field(
+        default_factory=dict, description="Social links"
+    )
+    custom_css: str | None = Field(None, description="Custom CSS")
+    css_variables: dict[str, str] | None = Field(
+        None, description="CSS custom properties"
+    )
+
+
+class ThemePresetPreview(BaseModel):
+    """Preview information for a theme preset."""
+
+    name: str = Field(..., description="Preset name")
+    description: str = Field(..., description="Preset description")
+    primary_color: str = Field(..., description="Primary color")
+    secondary_color: str = Field(..., description="Secondary color")
+    accent_color: str = Field(..., description="Accent color")
+    heading_font: str = Field(..., description="Heading font")
+    body_font: str = Field(..., description="Body font")
+    layout_style: str = Field(..., description="Layout style")
+
+
+class ThemePresetResponse(BaseModel):
+    """Response after applying a preset."""
+
+    message: str = Field(..., description="Success message")
+    theme: VendorThemeResponse = Field(..., description="Applied theme")
+
+
+class ThemePresetListResponse(BaseModel):
+    """List of available theme presets."""
+
+    presets: list[ThemePresetPreview] = Field(..., description="Available presets")
+
+
+class ThemeDeleteResponse(BaseModel):
+    """Response after deleting a theme."""
+
+    message: str = Field(..., description="Success message")