scripts/update.ps1: check manifest, stage+verify the new version, swap it in
alongside the running one (versions\<ver> + current.txt pointer), then launch
with CMBOT_DATA_DIR. Degrades to the local version on any failure; never
overwrites the running version. Rollback = edit current.txt.
Verified against a fake versioned layout: update, idempotent re-run, unreachable
source, no source, corrupt download (marker missing), malformed manifest.
Not yet wired into a real install layout (build.ps1 still ships flat onedir).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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