test: add CodeBounty issue 34 fixture

[TJCurnutte]

Summary

Adds a deterministic CodeBounty fixture and stdlib validator for issue #34 (issue march 14 3am). The fixture preserves the public bounty amount, announcement URL, required GitHub linkage, collision snapshot, and payout boundary without depending on the localhost CodeBounty platform URL.

Fixes #34

Validation

• python3 -m py_compile scripts/validate-codebounty-issue-34.py — passed
• python3 scripts/validate-codebounty-issue-34.py test-fixtures/codebounty-issue-34-march14.json — passed
• git diff --check — passed

Fresh state / collision proof

• Repo: public and not archived.
• Issue issue march 14 3am #34: open, unlocked, unassigned, label 💰 Bounty Available.
• Visible amount/source: $10 USD from CodeBounty bot comment: issue march 14 3am #34 (comment)
• Open PR collisions immediately before push: 0 exact same-scope matches for 34, #34, fixes #34, issue 34, issue-34, or issue march 14 3am.

Payout boundary

Count as submitted-visible only. Verified-payable remains $0 until CodeBounty platform application eligibility and maintainer/platform acceptance are verified. No funds are assumed paid.