ConfigSettingsInner seeds its local draft once from the config record and
never re-seeds it while the page stays open, but every autosave PUT still
sent the entire draft. Since PUT /api/config deep-merges onto disk, that
degenerates into a full overwrite for every field the UI's schema knows
about: if `hermes config set` (or another profile/session) changes a
schema-known key like fallback_providers while Settings is open, the next
autosave — triggered by editing any unrelated field — writes the stale
seed-time value back over it.
Diff the draft against the seed-time baseline and send only the changed
branches, so an untouched key is never resent and the backend's deep-merge
actually protects it.
chelsealong
5361867c6d