Refine global worktrees root save behavior

Author: Reekin

src/features/settings/components/SettingsView.test.tsx

@@ -789,6 +789,7 @@ describe("SettingsView Environments", () => {
         }),
       );
     });
+    expect(onUpdateWorkspaceSettings).not.toHaveBeenCalled();
   });
 
   it("does not clear an existing global worktrees root when saving project-only changes", async () => {
@@ -834,6 +835,24 @@ describe("SettingsView Environments", () => {
     });
   });
 
+  it("shows save errors for the global worktrees root when there are no projects", async () => {
+    const onUpdateAppSettings = vi
+      .fn()
+      .mockRejectedValue(new Error("Failed to save global worktrees root"));
+    renderEnvironmentsSection({
+      groupedWorkspaces: [],
+      onUpdateAppSettings,
+    });
+
+    const input = screen.getByLabelText("Global worktrees root");
+    fireEvent.change(input, { target: { value: "I:/cm-worktrees" } });
+    fireEvent.click(screen.getByRole("button", { name: "Save" }));
+
+    expect(
+      await screen.findByText("Failed to save global worktrees root"),
+    ).toBeTruthy();
+  });
+
   it("saves the setup script for the selected project", async () => {
     const onUpdateWorkspaceSettings = vi.fn().mockResolvedValue(undefined);
     renderEnvironmentsSection({ onUpdateWorkspaceSettings });

src/features/settings/components/sections/SettingsEnvironmentsSection.tsx

@@ -119,6 +119,9 @@ export function SettingsEnvironmentsSection({
             </button>
           </div>
         ) : null}
+        {!hasProjects && environmentError ? (
+          <div className="settings-agents-error">{environmentError}</div>
+        ) : null}
       </div>
 
       {!hasProjects ? (

src/features/settings/hooks/useSettingsEnvironmentsSection.ts

@@ -147,6 +147,7 @@ export const useSettingsEnvironmentsSection = ({
     const nextScript = environmentDraftNormalized;
     const nextGlobalFolder = globalWorktreesFolderDraft.trim() || null;
     const nextFolder = worktreesFolderDraft.trim() || null;
+    const workspaceSettingsDirty = environmentDirty || worktreesFolderDirty;
     setEnvironmentSaving(true);
     setEnvironmentError(null);
     try {
@@ -156,7 +157,7 @@ export const useSettingsEnvironmentsSection = ({
           globalWorktreesFolder: nextGlobalFolder,
         });
       }
-      if (environmentWorkspace) {
+      if (environmentWorkspace && workspaceSettingsDirty) {
         await onUpdateWorkspaceSettings(environmentWorkspace.id, {
           worktreeSetupScript: nextScript,
           worktreesFolder: nextFolder,