b6b8173ccb
The webhook pod now routes through headroom's MiniMax-M2.7 endpoint, but the
cost line in the AI-usage collapsible still read 'headroom glm-5.2:cloud'.
Resolve a single display_model at the top of review_pr (OPENCODE_MODEL env
wins, else headroom/{OLLAMA_MODEL}) and pass it to:
* the opencode subprocess (was already doing this on the same line, now
sharing the value)
* format_review_body so REVIEW_HEADER also reflects the actual run
* _render_collapsible_usage so the parenthetical reads
'({display_model} — free tier)' or '({display_model} — billed)'.
Test additions in tests/pilot/test_ai_review.py cover:
* the parenthetical picks up the passed-in model verbatim
* the full provider prefix survives (headroom/<id>) for the opencode path
* nonzero cost flips the inner clause from 'free tier' to 'billed'
* the existing nonzero-cost assertion flips to assert 'billed' instead
of dropping the parenthetical entirely