refactor: nix-files feedback reusing git status, eliminate resulting dead code

[Scott McMaster (scottmcmaster)]

Summary

Rewrite the feedback gathering for nix file diffs to reuse the revamped git::query::status, then get rid of all the code that deads, thereby avoiding having to port it to git2.

Test Plan

Updated and added unit tests.

Docs

• Docs updated (companion PR in darkmatter/nixmac-web: #___)
• No docs update needed

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[Scott McMaster (scottmcmaster)]

• refactor: migrate commit_all and create_evolution_backup staging to git2, kill git_command wrapper #319
• refactor: migrate checkout_files_at_commit, restore_all, and restore_from_branch_ref to git2 #311
• refactor: migrate intent_add_untracked to git2, setting INTENT_TO_ADD flag without shelling out #310
• refactor: remove git stash command and related functionality #291
• refactor: migrate create_evolution_backup internals to git2, remove get_head_sha wrapper #290
• refactor: migrate tag_commit to git2, remove unused delete_backup_branch #289
• refactor: update file_diff_contents to use git2 instead of CLI, make path helper more robust #283
• refactor: port the git log function from CLI to git2 #281
• refactor: nix-files feedback reusing git status, eliminate resulting dead code #278 👈 (View in Graphite)
• fix: split made_edit_or_build_check into separate flags and minor whitespace cleanup #288
• develop

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[github-actions]

📋 PR Overview

Lines changed	221 (+98 / -123)
Files	0 added, 3 modified, 0 deleted
Draft / WIP	no
Has Test Plan	yes
No Test Plan Needed	no
New UI components	no
New Storybook stories	no
New Rust modules	no
New TS source files	no
New tests	no
package.json touched	no
Cargo.toml touched	no
Infra / CI touched	no

🔬 Coverage

Report	Lines	Statements	Functions	Branches
apps/native/coverage/coverage-summary.json	26.3%	26.4%	24.2%	17.9%

Generated by 🚫 dangerJS against dea858b

[Copilot]

Pull request overview

Refactors feedback collection for “changed nix files” to reuse the git2-based git::query::status() implementation, and removes the now-dead CLI diff helpers/tests from the git exec layer.

Changes:

• Removes git::get_nix_diff (and its helper functions/tests) from git/exec.rs.
• Adds a feedback-local get_nix_diff() that derives .nix diffs from git::status().changes.
• Updates unit tests to cover the new diff-gathering path.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
apps/native/src-tauri/src/git/mod.rs	Stops re-exporting the removed get_nix_diff from the git exec surface.
apps/native/src-tauri/src/git/exec.rs	Deletes unused nix-diff generation helpers and their associated unit tests.
apps/native/src-tauri/src/feedback.rs	Reimplements nix diff gathering via git::status() and adds/updates tests for the new behavior.

[Juanpe Bolívar (arximboldi)]

Nice!