feat: add checkpoint postgres migration admin

offline-backend-20260512/backend/app/gateway/app.py

@@ -30,8 +30,9 @@ from app.gateway.routers import (
     artifacts,
     assistants_compat,
     auth,
-    channels,
-    feedback,
+    channels,
+    checkpoint_migration,
+    feedback,
     html_page_favorites,
     intent,
     llm_metrics,
@@ -905,7 +906,10 @@ This gateway provides custom endpoints for models, MCP configuration, skills, an
     app.include_router(tool_metrics.router)
 
     # Channels API is mounted at /api/channels
-    app.include_router(channels.router)
+    app.include_router(channels.router)
+
+    # Admin checkpoint migration API: SQLite legacy checkpoints -> Postgres.
+    app.include_router(checkpoint_migration.router)
 
     # Assistants compatibility API (LangGraph Platform stub)
     app.include_router(assistants_compat.router)