fix(deps): bump protobuf to 6.33.6 for VULN-88809

[shuningc]

Summary

• Remediate VULN-88809: ParseDict() DoS where max_recursion_depth is bypassed via nested google.protobuf.Any messages.
• poetry.lock: protobuf 6.31.1 → 6.33.6 (transitive; capped <7.0.0 by dependents; no pyproject change).
• Example pin elastic-chatbot-rag-app/requirements.txt: protobuf==5.29.6 (latest patched 5.x).

Test plan

• poetry check
• Installed protobuf 6.33.6; poetry run pytest tests/ (1988 passed, 10 skipped)

Jira

VULN-88809

[etserend]

Code Review — AI-Assisted Feedback

Reviewed by Claude Code (Claude Opus), automated review to assist human reviewers.

Verdict: Approve

Minimal, well-scoped fix. The dual-track patching strategy is correct and worth calling out explicitly.

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P3 — Dual-track patching (5.x + 6.x) not explained in PR description (Claude Code)

File/Section: poetry.lock vs examples/rag/elastic-chatbot-rag-app/requirements.txt
Issue: The main lockfile moves to protobuf 6.33.6 while the example pin stays on the 5.x line (5.29.3 → 5.29.6). This is the correct strategy — google-cloud-aiplatform dependents cap at <6.0.0 — but the PR description doesn't explain the two-track approach, which could confuse future reviewers.
Evidence: PR description notes "capped <7.0.0 by dependents"; both 5.29.5+ and 6.31.1+ received the CVE fix for VULN-88809.
Recommended fix: Add a brief note to the PR description explaining why both 5.x and 6.x lines are patched independently.

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Reviewer	Model	Key Contribution
Claude Code	Claude Opus	Flagged undocumented dual-track patching rationale