Removed:
- _resolve_model (L36, 2 lines)
- MODEL_MAP module-level dict (L29) — only consumed by the deleted
function, so it became orphaned after the cut.
Verified zero callers via:
grep -rn '_resolve_model' backend electron frontend/src
grep -rn 'MODEL_MAP' backend electron frontend/src
The only other MODEL_MAP match (browser_agent.py) is a distinct
module-level dict, not this one. 802 tests pass.