Fix BLOB result set handling in MySQL Proxy

[terrymanu]

No description provided.

[terrymanu]

Result

Review Result: Mergeable

The BLOB fix preserves raw bytes in both MySQL text and binary result paths, with focused success, failure, and stream-cleanup coverage. No current-head blocker remains.

Evidence

• Reviewed head: 06171bf26cd6.
• Both text results and binary results serialize Blob contents without text conversion and close the stream.
• MySQL protocol focused tests: 37 tests, 0 failures/errors; Maven exit 0.
• The two round-robin files are byte-identical to current base commit cb2a869 from Prevent negative round-robin index on counter overflow #39339, so they add no effective merge delta.

Coverage

• All six GitHub-authoritative files were accounted for; GitHub compare and local triple-dot scope matched.
• Reviewed clusters: BLOB serialization for text/prepared-statement results; upstream-duplicate round-robin changes.
• Completed root-cause, blast-radius/contracts, tests/runtime/operations, latest-delta, and full-scope convergence passes.
• No linked issue, public comments, reviews, or unresolved evidence gaps.
• Code-correctness result only; CI was not reviewed.