feat(vcs): compare folder selections with revisions across repositories (#602)

Compare with Branch or Revision only handled one file, so reviewing a folder meant opening each file. Folders, the project root and multiple selections now open a changes tree against the chosen revision, with per-file diffs on demand. A single file keeps its direct diff.

Each path resolves against its own repository through the root registry. In a multi-repo workspace the picker offers shared revisions such as "main in 3 repositories" as well as per-repository ones, results are grouped by repository, and content outside any repository or a repository missing the revision is stated in the result. Listing is cancellable and off the UI thread, includes worktree and untracked changes, and a rename leaving the selection shows as a delete. Show Diff on folders reuses the same tree.

Verified on macOS, and against a remote host over the server protocol. A remote window, Windows and Linux were not run.

Fixes #567

src-tauri/src/commands/mod.rs

@@ -271,6 +271,8 @@ pub fn builder() -> tauri_specta::Builder<tauri::Wry> {
         vcs::vcs_add_worktree,
         vcs::vcs_remove_worktree,
         vcs::vcs_diff_with_worktree,
+        vcs::vcs_compare_scope,
+        vcs::vcs_compare_paths,
         vcs::vcs_diff_revisions,
         vcs::vcs_merge_base,
         vcs::vcs_create_patch,

src-tauri/src/commands/vcs.rs

@@ -680,3 +680,26 @@ pub async fn vcs_shelf_import(
 ) -> IdeResult<()> {
     ide_host::ops::vcs::vcs_shelf_import(&state.host, window.label(), name, patch).await
 }
+
+#[tauri::command]
+#[specta::specta]
+pub async fn vcs_compare_scope(
+    window: Window,
+    state: State<'_, AppState>,
+    paths: Vec<PathBuf>,
+) -> IdeResult<ide_vcs::CompareScope> {
+    ide_host::ops::vcs::vcs_compare_scope(&state.host, window.label(), paths).await
+}
+
+#[tauri::command]
+#[specta::specta]
+pub async fn vcs_compare_paths(
+    window: Window,
+    state: State<'_, AppState>,
+    paths: Vec<PathBuf>,
+    revision: String,
+    repositories: Option<Vec<PathBuf>>,
+    request: RequestId,
+) -> IdeResult<ide_vcs::CompareResult> {
+    ide_host::ops::vcs::vcs_compare_paths(&state.host, window.label(), paths, revision, repositories, request).await
+}