ci: update Claude dependency review workflow

[Nsttt]

Summary

Updates the organization Claude workflow to the current stable action and Sonnet model, replaces deprecated action inputs, and tightens both review prompts.

Claude may autonomously approve only Dependabot or Renovate PRs. The model returns a structured decision; fixed workflow steps enforce the bot identity, authenticated event actor, non-draft state, same-repository head, exact reviewed SHA, and verified bot-only commits before submitting approval.

Changes

• Pin anthropics/claude-code-action v1.0.209 and use Claude Sonnet 5
• Use action defaults for summary reviews; explicitly grant only inline-comment MCP access for full reviews
• Keep workflow credentials and approval commands outside the model process
• Route dependency bots through pull_request_target without checking out PR-head code
• Dismiss earlier workflow approvals before reviewing a new bot PR state
• Preserve one updated summary comment and include prior inline comments for deduplication

Security note

The approval decision intentionally remains model-driven, per the requested behavior. Before marking this PR ready, consuming repositories should enforce dismissal of stale approvals or require approval of the latest push. A workflow cannot make approval invalidation atomic with a head update by itself.

Testing

• actionlint .github/workflows/claude.yml
• git diff --check
• Live GitHub API provenance checks against Zephyr Dependabot and Renovate PRs
• Negative provenance fixture rejecting a non-bot commit author
• Structured pre-ship review; actionable workflow defects fixed, model-authorization tradeoff documented above