Preserve upstream fixes without restoring retired dependency installers.
Run configured-feature checks in the selected build interpreter. Reuse a
supported base Python during bootstrap, and preserve durable backup media.
Refresh the dependency lock through PM. Keep the frozen historical import
surface unchanged. Adapt incoming native tests to the platform markers.
Verification: the incoming 86-file pass found two fixture mismatches;
both passed after correction. Targeted PM/update/compatibility checks,
Electron and renderer typechecks, and desktop tests passed.
Native Windows/macOS update journeys and the full suite remain unrun.
b681f0c50e