STEP_034G2_DIAGNOSE_CREATE_FAILURE PASS_CREATE_FAILURE_DIAGNOSED
timestamp: 20260708-121045

Validation:
- peers_now_count: 20
- jobs_now_count: 36
- error_related_lines: 26
- schema_lines: 11
- smoke_related_lines: 3
- backend_health_ok_lines: 2

Changes:
- none
- no POST retry
- no peer creation
- no cancel/disable
- no WG reload
- no backend restart

Next:
- fix create payload or endpoint call based on backend error/schema, then retry create once with guarded counts.