Fix CI: title removal order, Windows fixtures and POSIX-only tests

- Title removal ran the Steam shortcut tidy-up before steamos-delete, which
  finds the Proton prefix through that shortcut, so compatdata was left behind
  (e2e caught it). steamos-delete runs first again; art/collection tidy-up after.
- Test fixtures are byte-exact: never convert line endings (a text-looking
  fixture APK got CRLF on Windows and failed its SHA-256).
- Read index.html/artwork-settings.js as UTF-8 in tests; app-data backup and
  OBB shell tests run only on POSIX (they exercise the Frame-side scripts).
- e2e expects the icon under artwork/ now.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

tests/test_library_entrypoints.py

@@ -216,6 +216,19 @@ class EntryPoints(unittest.TestCase):
             titles.remove('Game')
         self.assertTrue(any('steamos-delete --delete-title Game' in c for c in cmds))
 
+    def test_native_remove_deletes_before_tidying_the_shortcut(self):
+        # steamos-delete finds the Proton prefix through the shortcut, so the shortcut must still exist.
+        order = []
+        def ssh(cmd, **kwargs):
+            if 'steamos-delete' in cmd:
+                order.append('delete')
+            return 'yes' if 'test -d' in cmd else '/home/steamos' if 'HOME' in cmd else ''
+        with patch.object(titles, 'ssh', side_effect=ssh), patch.object(titles, 'ensure_utils'), \
+             patch.object(titles, '_library_shortcut', return_value=42), \
+             patch.object(titles.frame_android, 'shortcut_tool', side_effect=lambda *a: order.append(a)):
+            titles.remove('Game')
+        self.assertEqual(order, ['delete', ('remove', '42')])
+
     def test_native_refresh_art_backfills_registered_title(self):
         meta = {'id':'Game','name':'My Game','source':'game.zip'}
         writes = []