attempt_needs_retry triggers on runtime error / empty output / non-object
result (GLM StructuredOutput text-return case) / is_error (1301 etc);
content-quality failures do NOT trigger (a provider switch won't fix them).
Flow: attempt1 primary → attempt2 same provider (10s backoff) → attempt3
FALLBACK_PROVIDER via resolve_continue_provider with its budget override
(ccswitch-gpt=30). Idempotent end-to-end (7-day registry dedup + slug-keyed
push), so re-runs only fill gaps; per-attempt raw outputs kept as *.attemptN.
Verified decision matrix: success/runtime-error/invalid-output/api-error/
business-fail.