feat: complete CMS as fully autonomous self-contained module

Transform CMS from a thin wrapper into a fully self-contained module with
all code living within app/modules/cms/:

Module Structure:
- models/: ContentPage model (canonical location with dynamic discovery)
- schemas/: Pydantic schemas for API validation
- services/: ContentPageService business logic
- exceptions/: Module-specific exceptions
- routes/api/: REST API endpoints (admin, vendor, shop)
- routes/pages/: HTML page routes (admin, vendor)
- templates/cms/: Jinja2 templates (namespaced)
- static/: JavaScript files (admin/vendor)
- locales/: i18n translations (en, fr, de, lb)

Key Changes:
- Move ContentPage model to module with dynamic model discovery
- Create Pydantic schemas package for request/response validation
- Extract API routes from app/api/v1/*/ to module
- Extract page routes from admin_pages.py/vendor_pages.py to module
- Move static JS files to module with dedicated mount point
- Update templates to use cms_static for module assets
- Add module static file mounting in main.py
- Delete old scattered files (no shims - hard errors on old imports)

This establishes the pattern for migrating other modules to be
fully autonomous and independently deployable.

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

app/modules/cms/routes/pages/admin.py

@@ -0,0 +1,104 @@
+# app/modules/cms/routes/pages/admin.py
+"""
+CMS Admin Page Routes (HTML rendering).
+
+Admin pages for managing platform and vendor content pages.
+"""
+
+from fastapi import APIRouter, Depends, Path, Request
+from fastapi.responses import HTMLResponse, RedirectResponse
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_db, require_menu_access
+from app.templates_config import templates
+from models.database.admin_menu_config import FrontendType
+from models.database.user import User
+
+router = APIRouter()
+
+
+# ============================================================================
+# CONTENT PAGES MANAGEMENT
+# ============================================================================
+
+
+@router.get("/platform-homepage", include_in_schema=False)
+async def admin_platform_homepage_manager(
+    request: Request,
+    current_user: User = Depends(require_menu_access("platforms", FrontendType.ADMIN)),
+    db: Session = Depends(get_db),
+):
+    """
+    Deprecated: Redirects to platforms page.
+
+    Platform homepages are now managed via:
+    - /admin/platforms → Select platform → Homepage button
+    - Or directly: /admin/content-pages?platform_code={code}&slug=home
+    """
+    return RedirectResponse(url="/admin/platforms", status_code=302)
+
+
+@router.get("/content-pages", response_class=HTMLResponse, include_in_schema=False)
+async def admin_content_pages_list(
+    request: Request,
+    current_user: User = Depends(require_menu_access("content-pages", FrontendType.ADMIN)),
+    db: Session = Depends(get_db),
+):
+    """
+    Render content pages list.
+    Shows all platform defaults and vendor overrides with filtering.
+    """
+    return templates.TemplateResponse(
+        "cms/admin/content-pages.html",
+        {
+            "request": request,
+            "user": current_user,
+        },
+    )
+
+
+@router.get(
+    "/content-pages/create", response_class=HTMLResponse, include_in_schema=False
+)
+async def admin_content_page_create(
+    request: Request,
+    current_user: User = Depends(require_menu_access("content-pages", FrontendType.ADMIN)),
+    db: Session = Depends(get_db),
+):
+    """
+    Render create content page form.
+    Allows creating new platform defaults or vendor-specific pages.
+    """
+    return templates.TemplateResponse(
+        "cms/admin/content-page-edit.html",
+        {
+            "request": request,
+            "user": current_user,
+            "page_id": None,  # Indicates this is a create operation
+        },
+    )
+
+
+@router.get(
+    "/content-pages/{page_id}/edit",
+    response_class=HTMLResponse,
+    include_in_schema=False,
+)
+async def admin_content_page_edit(
+    request: Request,
+    page_id: int = Path(..., description="Content page ID"),
+    current_user: User = Depends(require_menu_access("content-pages", FrontendType.ADMIN)),
+    db: Session = Depends(get_db),
+):
+    """
+    Render edit content page form.
+    Allows editing existing platform or vendor content pages.
+    """
+    return templates.TemplateResponse(
+        "cms/admin/content-page-edit.html",
+        {
+            "request": request,
+            "user": current_user,
+            "page_id": page_id,
+        },
+    )