Clarify turn-end review gate behavior

[mychaelconnolly]

Summary

Clarifies the optional review gate as a turn-end blocking review of the previous Codex turn.

The gate now documents and tests the intended model behavior: it does not pass --model or --effort, so Claude Code
uses the user's configured defaults. $cc:setup also surfaces detected Claude defaults where readable.

Notes

This branch is stacked on #57, which moves review execution to the read-only git MCP path. After #57 merges, this PR
should be rebased so only the turn-end gate/docs/default-detection changes remain.

Changes

• Rename public gate language from stop-time/Ctrl+C to turn-end review gate.
• Fix reverse-plugin wording that said "previous Claude turn" instead of "previous Codex turn".
• Add trigger: "turn-end" to gate snapshots.
• Document that the gate inherits Claude Code defaults.
• Add setup output for detected Claude default model/effort.
• Add tests proving the gate does not send --model or --effort.

Validation

• npm run lint
• npm run typecheck
• npm run check:version-sync
• npm run check:changelog
• npm test
• npm run test:integration
• Targeted setup E2E: 3 passing

Full E2E still has existing background routing failures under Codex CLI 0.141.0; setup/review-gate E2E paths pass.

[sf-jin-ku]

Kept the contributor's turn-end terminology, removed speculative settings detection and extra metadata, corrected timeout docs to the fail-closed implementation, and verified 172 targeted tests.