- Match code 110 (billing daily count exceeded) alongside 112/10605/pricingUrl
in isBillingBlock, parsing JSON safely and accepting numeric/string codes
- Accept numeric strings for statusCodeValue and object bodies in envelope peek
- Emit structured 403 quota error chunk instead of synthetic assistant text
when a billing envelope appears mid-stream
- Preserve upstream HTTP status in handleForcedSSEToJson when error chunk carries
a valid 400-599 status
- Add unit tests for code-110 detection, mid-stream billing envelopes, and false-positive guard
