bug(codex): incidental 429 digits are classified as provider rate limits #3175

On official dev 12cb5f9d5378bb9cbe5160caedb16fac72b5ca1f, _classify_codex_failure treats any occurrence of the digits 429 as a provider rate limit. A failed tool message such as 2026-10-01T12:30:14.429Z failed to spawn tool process or connection refused at localhost:4299 therefore returns HTTP 429 instead of a generic execution error (500). A timestamp containing those digits can also override a real authentication diagnostic.

Reproduction: construct ExecutionMetadata(error_message=...) with either example and call _classify_codex_failure(1, "", metadata) in docker/base-image/agent_server/services/codex_runtime.py. The same result reproduces through parse_codex_jsonl with a turn.failed error message. No provider account or live service is required. Tested under Python 3.12.

Expected: incidental digits do not establish rate limiting. Preserve explicit HTTP/status 429 and existing named rate/quota markers.

A small candidate requiring status context for numeric 429 has regression tests failing on stock dev and passing after the change. This report is deliberately limited to numeric false positives; it does not propose changing competing-error precedence or all provider error classification.