Adds website theme serialization system

backend/app/api/mobile_builds.py

@@ -305,6 +305,25 @@ async def _upload_files_to_worker(
             raise RuntimeError(f"Failed to upload file {row.original_name}: {out}")
 
 
+async def _upload_theme_to_worker(
+    session: AsyncSession,
+    request: MobileBuildRequest,
+    host: str,
+) -> None:
+    """SCP theme.json to the build worker (no-op if file doesn't exist)."""
+    theme_path = Path(settings.THEME_JSON_PATH)
+    if not theme_path.exists():
+        await _append_log(session, request, "[theme] theme.json not found — skipping upload")
+        return
+
+    scp_prefix = _build_scp_prefix(host)
+    remote_target = f"{settings.MOBILE_BUILD_SSH_USER}@{host}:{settings.MOBILE_BUILD_REMOTE_APP_DIR}/theme.json"
+    code, out = await _run_command(scp_prefix + [str(theme_path), remote_target])
+    if code != 0:
+        raise RuntimeError(f"Failed to upload theme.json: {out}")
+    await _append_log(session, request, "[theme] theme.json uploaded to worker")
+
+
 async def _run_platform_build(
     session: AsyncSession,
     request: MobileBuildRequest,
@@ -317,6 +336,9 @@ async def _run_platform_build(
     await _append_log(session, request, f"[{platform}] Uploading {len(platform_files)} file(s) to worker")
     await _upload_files_to_worker(platform_files, host)
 
+    # Upload theme.json to worker
+    await _upload_theme_to_worker(session, request, host)
+
     ssh_prefix = _build_ssh_prefix(host)
     cmd = ssh_prefix + [
         (