fix: harden tempo transaction verification

[emmajam]

Summary

• Enforce challenge-bound attribution memo checks for Tempo transaction credentials, matching the hash credential path.
• Reserve computed raw transaction hashes before broadcast when replay protection storage is configured.
• On duplicate transaction credentials, fetch and validate the existing receipt instead of rebroadcasting.
• Release reservations for submission errors while keeping receipt/validation failures reserved for retry safety.
• Added a patch changelog entry and regression tests. Confirmed uv run ruff check ., uv run pyright, and uv run pytest -q pass.