feat(other): guide standalone users to settings.json from the no-paths empty state

The standalone empty state showed the folder_paths keys but not where to
put them, and its Open Settings button led to a modal that cannot edit
primary folder paths. Now the page shows the real settings.json path and
an Open Settings Folder button backed by the existing open-location API.

Also stop open_settings_location from claiming success on headless Linux
sessions: with no DISPLAY/WAYLAND_DISPLAY, xdg-open cannot work, so the
handler now returns clipboard mode and the browser copies/shows the path
instead.

tests/frontend/pages/otherDisabledPage.test.js

@@ -25,6 +25,7 @@ describe('Other Models disabled page', () => {
         document.body.innerHTML = [
             '<button id="enableOtherModelsBtn"></button>',
             '<button id="openOtherModelsSettingsBtn"></button>',
+            '<button id="openSettingsFolderBtn"></button>',
         ].join('');
 
         Object.defineProperty(window, 'location', {
@@ -64,6 +65,52 @@ describe('Other Models disabled page', () => {
         expect(showModal).toHaveBeenCalledWith('settingsModal');
     });
 
+    it('reveals the settings.json location from the standalone no-folders state', async () => {
+        global.fetch = vi.fn().mockResolvedValue({
+            ok: true,
+            json: async () => ({ success: true, message: 'Opened settings folder' }),
+        });
+
+        const button = document.getElementById('openSettingsFolderBtn');
+        button.dispatchEvent(new MouseEvent('click', { bubbles: true }));
+        await vi.waitFor(() => expect(showToastMock).toHaveBeenCalled());
+
+        expect(global.fetch).toHaveBeenCalledWith(
+            '/api/lm/settings/open-location',
+            expect.objectContaining({ method: 'POST' }),
+        );
+        expect(showToastMock).toHaveBeenCalledWith(
+            'settings.openSettingsFileLocation.success',
+            {},
+            'success',
+        );
+        expect(button.disabled).toBe(false);
+    });
+
+    it('copies the settings path to the clipboard in Docker mode', async () => {
+        const writeText = vi.fn().mockResolvedValue(undefined);
+        Object.defineProperty(navigator, 'clipboard', {
+            value: { writeText },
+            configurable: true,
+        });
+        global.fetch = vi.fn().mockResolvedValue({
+            ok: true,
+            json: async () => ({ success: true, mode: 'clipboard', path: '/data/settings.json' }),
+        });
+
+        document.getElementById('openSettingsFolderBtn').dispatchEvent(
+            new MouseEvent('click', { bubbles: true }),
+        );
+        await vi.waitFor(() => expect(showToastMock).toHaveBeenCalled());
+
+        expect(writeText).toHaveBeenCalledWith('/data/settings.json');
+        expect(showToastMock).toHaveBeenCalledWith(
+            'settings.openSettingsFileLocation.copied',
+            { path: '/data/settings.json' },
+            'success',
+        );
+    });
+
     it('enables Other Models through the settings API and reloads', async () => {
         global.fetch = vi.fn().mockResolvedValue({
             ok: true,