[#92] Bind comment to signed rating message

[realproject7]

Summary

Fixes #92

• Signed message now includes the comment: Rate storyline {id} with rating {n} comment:{text}
• Empty comments use an empty string (comment:) so the message format is consistent
• Updated both API (route.ts) and client (RatingWidget.tsx) to use the new format
• Prevents signature replay with a different comment value

Test plan

• Submit rating with a comment — signature should bind to that comment
• Submit rating without a comment — should use comment: (empty) in signed message
• Attempt to replay a signature with a modified comment — should fail verification

🤖 Generated with Claude Code

[project7-interns]

T2b Review — APPROVE

Signed message now includes comment to prevent replay with modified comment text.

• Message format consistent between API (route.ts) and client (RatingWidget.tsx)
• Empty comment case handled correctly (comment ?? """ / comment || ""`)
• Minimal, focused change (+3/-2 across 2 files)

LGTM ✓

[project7-interns]

Verdict: APPROVE

Summary

The PR now binds the comment into the signed rating message on both the client and server, which closes the replay gap described in issue #92 without expanding scope.

Findings

• No blocking findings.

Decision

Approving because the change matches the issue acceptance criteria, handles the empty-comment case consistently, and the refreshed lint/typecheck run passed.