Fix query link creation for new record identity API

[atimin]

Closes #

Please check if the PR fulfills these requirements

• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• CHANGELOG.md has been updated (for bug fixes / features / docs)

What kind of change does this PR introduce?

Bug fix

What was changed?

• Updated query link payload serialization to include record_entry and record_timestamp.
• Kept sending legacy index for compatibility with older API behavior.
• Updated Bucket.createQueryLink to resolve recordIndex to an exact record identity (entry + timestamp) using metadata query results before creating the link.
• Added validation for recordIndex to ensure it is a non-negative integer.

Related issues

reductstore/reductstore#1332

Does this PR introduce a breaking change?

No. Public API remains the same (recordIndex parameter is still accepted), and payload now supports the new server requirements.

Other information:

Validation run:

• npm run fmt:check
• npm run lint
• npm run tsc
• npx vitest run test/Bucket.test.ts -t "query link" --reporter=verbose (against patched local server)