chore(frontend): regenerate openapi.json with TaskDecompositionResponse.created_at

The created_at field was added to TaskDecompositionResponse a few commits
back but openapi.json was never regenerated, so the check-api-types CI
job (which re-exports the schema and asserts no diff) was failing.
Re-exporting via poetry run export-api-schema and prettier.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

autogpt_platform/frontend/src/app/api/openapi.json

@@ -14097,6 +14097,12 @@
             "title": "Auto Approve Seconds",
             "description": "Seconds the client should count down before auto-approving. Kept in sync with the server-side fallback timer, which runs a grace period longer to absorb network latency.",
             "default": 60
+          },
+          "created_at": {
+            "type": "string",
+            "format": "date-time",
+            "title": "Created At",
+            "description": "UTC timestamp when the tool returned. The client uses this with auto_approve_seconds to compute the correct remaining countdown when the user reopens the session — so the timer reflects real elapsed time instead of restarting from zero."
           }
         },
         "type": "object",