feat: support uploaded images in debug voice preview

Allow paste/drag temporary image assets so vision turns work without a live camera frame.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/app.py

@@ -26,6 +26,7 @@ from routes import (
     auth,
     conversations,
     health,
+    input_assets,
     knowledge_bases,
     mcp_servers,
     model_registry,
@@ -60,6 +61,7 @@ app.add_middleware(
 app.include_router(health.router)
 app.include_router(auth.router)
 app.include_router(conversations.router)
+app.include_router(input_assets.router)
 app.include_router(assistants.router)
 app.include_router(knowledge_bases.router)
 app.include_router(mcp_servers.router)