fix(tools): make apply_patch replacement explicit and compatible

[Angel-Hair]

Summary

apply_patch accepts a changes parameter that performs full file replacement, not patching. The name is easily confused with the patch parameter (which applies a unified diff). When both are passed simultaneously, changes silently takes precedence and patch is discarded — no error, no warning, and the file is overwritten with only the changes content.

Root cause

In execute(), the changes branch returns immediately if present, making the patch branch unreachable. The JSON schema declares oneOf mutual exclusivity, but this is advisory — the Rust handler enforces precedence, not rejection.

Fix

• Rename changes to replace across JSON schema, code, function names, enum variants, error messages, and tests
• Add explicit conflict detection: if both patch and replace are present, return an error telling the model to choose one

Testing

• cargo fmt -- --check
• cargo clippy -p codewhale-tui (zero warnings)
• cargo check -p codewhale-tui
• cargo test -p codewhale-tui -- tools::apply_patch (26/26 passed)

Checklist

• Updated docs or comments as needed
• Added or updated tests where relevant
• Verified TUI behavior manually if UI changes
• Harvested/co-authored credit uses a GitHub numeric noreply address

[github-actions]

Thanks @Angel-Hair for taking the time to contribute.

This repository is observing a maintainer-managed PR intake gate in dry-run mode, so this pull request is staying open. This note helps maintainers prepare the allowlist before any enforcement is considered.

Please read CONTRIBUTING.md for the expected contribution shape. A maintainer can grant recurring PR access by commenting /lgtm on a pull request.

[Hmbown]

Maintainer compatibility amendment is now on the contributor branch at e23cd2b9f.

The original report and contributor commit remain intact. The follow-up keeps replace as the canonical field while accepting deprecated changes, routes execution, preflight, repo-law, approval, diagnostics, and UI previews through one parser, and rejects all three ambiguous pairs before any file write (patch + replace, patch + changes, and replace + changes). It also corrects the Responses schema constraint note that failed the first macOS/Windows run.

Verification on the identical final source tree: 29 apply-patch tests; Responses and schema-sanitizer regressions; repo-law, approval-key, approval-preview, edited-path, and tool-routing coverage; cargo check -p codewhale-tui; formatting and diff checks. Fresh exact-head CI is now the final merge gate.

Thank you @Angel-Hair for finding and fixing the silent precedence bug.