record_resident_fits called save_models(), which writes the config manager's
own view of models.json -- a view that never saw this change. Verified live
2026-10-29: after a run that learned the model does not fit, the flag was set
in memory (the next load in the same process correctly skipped the resident
attempt, 110.6s instead of 865.3s) while models.json still read

    measured_resident_fits = None

so every restart would have paid the ~16 minute discovery again.

persist_model_field is the right call and is what record_vram_delta already
uses for measured_vram_gb: it re-reads models.json from disk, sets one field
and writes back, so a stale in-memory copy cannot revert a UI edit made
meanwhile. It also targets the entry by config_id, so two configs sharing one
checkpoint path do not overwrite each other's measurement.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014T3rZozi1Ehk96NG1WesgC