* fix(googlechat): keep accounts.default streaming when doctor migrates named accounts
* fix(googlechat): canonicalize migrated streaming
Replace the layered doctor migration with canonical root/default/account materialization and prove runtime resolution matches the stored config.\n\nCo-authored-by: tiffanychum <71036662+tiffanychum@users.noreply.github.com>
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Co-authored-by: Peter Steinberger <steipete@gmail.com>