[purp]

Summary

Recover missing or incomplete /label-issue patches from GitHub's raw PR diff. Complete evidence can proceed through the existing preview and apply checks; failed recovery continues to block label writes.

Related Issue

Closes #5583

Relates to #5151 and #5276.

Changes

• Fetch one raw diff per files refresh when per-file patches are incomplete. Match old/new file paths, validate every hunk and changed-line count, and verify the prepared head/base around fetching.
• Record recovery provenance, source digest, byte count and revisions. Preserve partial coverage with a diagnostic when recovery fails.
• Preserve raw response line endings and reject invalid UTF-8. Retain transport size, timeout, retry and mutation protections.
• Document recovery in the /label-issue command reference.

The existing 2 MiB response bound applies. Binary or metadata-only changes without text hunks remain partial; classifier context budgeting is separate.

Release Notes

Testing

• 197 offline labeling tests pass with warnings treated as errors: uv run --no-project --offline --python /usr/bin/python3 python -W error -m unittest discover -s tasks/scripts -p 'label_issue*_test.py' -q.
• Added recovery, file identity, truncation, malformed input, revision race, transport, and preview/apply coverage. Failed recovery produces no writes in the application test.
• Read-only live preparation recovered the omitted patches on feat(policy): add managed maximum permission modes #2168 (crates/openshell-server/src/grpc/policy.rs) and feat(api)!: model CPU and memory as typed compute resource requirements #3012 (sdk/go/proto/openshellv1/openshell.pb.go), with complete files coverage. No live labels changed.
• Ruff lint/format checks and git diff --check pass for the changed files.
• Reviewed related contributor guidance using the sync-agent-infra maintenance map and reviewed the diff with omit-needless-words; no further changes required.

Checklist

• Follows Conventional Commits
• Commits are signed off (DCO)
• Relevant labeling workflow documentation updated