fix(ui): harden RTL sidebar and desktop window controls

Keep custom Windows/Linux controls available during platform detection, preserve RTL table order while aligning filenames left, and persist sidebar placement overrides.

Refs #17

src/utils/platform.test.ts

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest';
+import { shouldUseCustomWindowControls } from './platform';
+
+describe('shouldUseCustomWindowControls', () => {
+  it('keeps custom controls present while Windows/Linux detection is unresolved', () => {
+    expect(shouldUseCustomWindowControls('unknown', 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)')).toBe(true);
+    expect(shouldUseCustomWindowControls('unknown', 'Mozilla/5.0 (X11; Linux x86_64)')).toBe(true);
+  });
+
+  it('does not render custom controls for macOS', () => {
+    expect(shouldUseCustomWindowControls('unknown', 'Mozilla/5.0 (Macintosh; Intel Mac OS X 14_0)')).toBe(false);
+    expect(shouldUseCustomWindowControls('macos', 'Mozilla/5.0 (Macintosh; Intel Mac OS X 14_0)')).toBe(false);
+  });
+
+  it('only opts into the supported desktop platforms', () => {
+    expect(shouldUseCustomWindowControls('windows', 'Mozilla/5.0 (Windows NT 10.0; Win64; x64)')).toBe(true);
+    expect(shouldUseCustomWindowControls('linux', 'Mozilla/5.0 (X11; Linux x86_64)')).toBe(true);
+    expect(shouldUseCustomWindowControls('android', 'Mozilla/5.0 (Linux; Android 14)')).toBe(false);
+  });
+});

src/utils/platform.ts

@@ -9,6 +9,9 @@ const fallback: PlatformInfo = {
   portable: false
 };
 
+export const shouldUseCustomWindowControls = (os: string, userAgent: string): boolean =>
+  !userAgent.includes('Mac') && (os === 'windows' || os === 'linux' || os === 'unknown');
+
 let cached: PlatformInfo | null = null;
 let pending: Promise<PlatformInfo> | null = null;