feat: add platform homepage and content management system with improved UI

Implemented a comprehensive CMS for managing platform homepage and content pages:

- Platform homepage manager with template selection (default, minimal, modern)
- Content pages CRUD with platform defaults and vendor overrides
- Sidebar navigation for Content Management section
- Dedicated API endpoints for creating, updating, deleting pages
- Template support for customizable homepage layouts
- Header/footer navigation integration for content pages
- Comprehensive documentation for platform homepage setup
- Migration script for creating initial platform pages

UI improvements:
- Fixed action buttons styling in content pages table to match design system
- Added proper hover states, rounded corners, and better contrast
- Increased button size and padding for better usability

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/routes/admin_pages.py

@@ -21,6 +21,10 @@ Routes:
 - GET /users         → User management page (auth required)
 - GET /imports       → Import history page (auth required)
 - GET /settings      → Settings page (auth required)
+- GET /platform-homepage → Platform homepage manager (auth required)
+- GET /content-pages → Content pages list (auth required)
+- GET /content-pages/create → Create content page (auth required)
+- GET /content-pages/{page_id}/edit → Edit content page (auth required)
 """
 
 from fastapi import APIRouter, Request, Depends, Path
@@ -306,6 +310,89 @@ async def admin_settings_page(
     )
 
 
+# ============================================================================
+# CONTENT MANAGEMENT SYSTEM (CMS) ROUTES
+# ============================================================================
+
+@router.get("/platform-homepage", response_class=HTMLResponse, include_in_schema=False)
+async def admin_platform_homepage_manager(
+        request: Request,
+        current_user: User = Depends(get_current_admin_from_cookie_or_header),
+        db: Session = Depends(get_db)
+):
+    """
+    Render platform homepage manager.
+    Allows editing the main platform homepage with template selection.
+    """
+    return templates.TemplateResponse(
+        "admin/platform-homepage.html",
+        {
+            "request": request,
+            "user": current_user,
+        }
+    )
+
+
+@router.get("/content-pages", response_class=HTMLResponse, include_in_schema=False)
+async def admin_content_pages_list(
+        request: Request,
+        current_user: User = Depends(get_current_admin_from_cookie_or_header),
+        db: Session = Depends(get_db)
+):
+    """
+    Render content pages list.
+    Shows all platform defaults and vendor overrides with filtering.
+    """
+    return templates.TemplateResponse(
+        "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(get_current_admin_from_cookie_or_header),
+        db: Session = Depends(get_db)
+):
+    """
+    Render create content page form.
+    Allows creating new platform defaults or vendor-specific pages.
+    """
+    return templates.TemplateResponse(
+        "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(get_current_admin_from_cookie_or_header),
+        db: Session = Depends(get_db)
+):
+    """
+    Render edit content page form.
+    Allows editing existing platform or vendor content pages.
+    """
+    return templates.TemplateResponse(
+        "admin/content-page-edit.html",
+        {
+            "request": request,
+            "user": current_user,
+            "page_id": page_id,
+        }
+    )
+
+
 # ============================================================================
 # DEVELOPER TOOLS - COMPONENTS & TESTING
 # ============================================================================