Adds website theme serialization system

backend/app/api/theme.py

@@ -0,0 +1,52 @@
+"""Theme export: public JSON endpoint, status check, and admin regeneration trigger."""
+
+from typing import Any, Dict
+
+from fastapi import APIRouter, Depends, HTTPException, status
+
+from app.auth import get_current_admin_user
+from app.theme_export import get_theme_status, write_theme_json
+from app.user_models import User
+
+router = APIRouter()
+
+
+@router.get("/status")
+async def theme_status() -> Dict[str, Any]:
+    """Return theme.json file status. Public endpoint."""
+    return get_theme_status()
+
+
+@router.get("")
+async def get_theme() -> Dict[str, Any]:
+    """Return the current theme as a JSON dict. Public endpoint.
+
+    Also regenerates the theme.json file on disk as a side effect,
+    ensuring the file is always up-to-date.
+    """
+    try:
+        theme = await write_theme_json()
+    except Exception as e:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Failed to generate theme: {e}",
+        )
+    return theme
+
+
+@router.post("/regenerate", status_code=200)
+async def regenerate_theme(
+    _: User = Depends(get_current_admin_user),
+) -> Dict[str, Any]:
+    """Force regenerate the theme.json file. Admin only.
+
+    Returns the newly generated theme dict.
+    """
+    try:
+        theme = await write_theme_json()
+    except Exception as e:
+        raise HTTPException(
+            status_code=status.HTTP_500_INTERNAL_SERVER_ERROR,
+            detail=f"Failed to regenerate theme: {e}",
+        )
+    return theme