Two cleanups from review.
The offline walk matched a served turn to its `model_change` by also
accepting a `:level` thinking suffix, but no writer produces one: every
`appendModelChange` call site records a bare `provider/id` or a
`formatModelStringWithRouting` selector, and only the latter decorates —
with `@upstream`, never a level. Speculative matching in the part of the
change that already reconstructs the most from raw strings. Removed, with
its test narrowed to the format writers actually emit.
Attribution was also retained for the life of the recovery component, so
switching sessions in place could report a model from a different
transcript by name. It is now tagged with the session file it was earned
in and ignored when that no longer matches — the same self-invalidating
anchor `#ensurePersistedMessageKeys` uses, so no mutation call site has
to remember to clear anything. Anchoring on the file rather than the leaf
keeps attribution across compaction and appends, which stay within the
transcript that earned it.
enieuwy
a06a7f5ef1