fix: avoid embedding large adversarial review diffs

[dkundel-openai]

Summary

• Fixes /codex:adversarial-review failing on larger diffs by using the initial changed-file count to decide whether to inline the diff.
• Keeps inline diff context for small review scopes.
• Uses lightweight review context for larger scopes and instructs Codex to inspect the target diff itself with read-only git commands.
• Adds regression coverage for both inline and self-inspection paths.

Closes #11

Testing

• node --test tests/git.test.mjs tests/runtime.test.mjs tests/commands.test.mjs

[chatgpt-codex-connector]

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[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: f4d107092d

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".