A transient HTTP 500 during the range probe aborted bundle staging.
Retry PM-owned requests and body transfers with one bounded policy,
instead of retrying complete installs or stacking caller retry loops.
Keep partial ranges across attempts and interrupt backoff on pause.
Keep the CDN serial fallback active until its source finishes. Do not
retry permanent HTTP errors, certificate failures, bad hashes or disk
errors. Use the same policy for metadata reads and artifact hashing.
Verified: 217 focused tests passed, 1 skipped, and Ruff passed on the
changed Python files. The pinned Windows ARM64 uv archive also survived
an injected HTTP 500 through the PM CLI and its installed binary ran.
The full suite and desktop release build were not run.
8e4a804f53