Fix wallpaper upgrade compatibility and Settings icon clipping

Allow installed releases to omit the two newer appearance wallpapers while keeping new bundle verification strict. Fit the Settings header symbol within its square slot without clipping.

Verified 30 installer tests, the real upgrade dry-run, and release rendering previews on GPU and software backends.

scripts/tests/test_portal_install.py

@@ -112,6 +112,36 @@ m.main()
         for name in ('ferese-session', 'ferese-session-shell', 'ferese-screenshot'):
             self.assertEqual((self.bundles[0] / name).stat().st_mode & 0o777, 0o755)
 
+    def without_appearance_wallpapers(self, bundle):
+        manifest_path = bundle / 'manifest.json'
+        manifest = json.loads(manifest_path.read_text())
+        removed = {'wallpapers/ferese-wallpaper-dark.jpg', 'wallpapers/ferese-wallpaper-light.png'}
+        for target in removed:
+            (bundle / target).unlink()
+
+        manifest['files'] = [item for item in manifest['files'] if item['target'] not in removed]
+        manifest_path.write_text(json.dumps(manifest))
+
+    def test_upgrade_and_rollback_accept_installed_release_before_appearance_wallpapers(self):
+        self.install()
+        legacy = self.base / 'releases/first'
+        self.without_appearance_wallpapers(legacy)
+        self.install(1)
+        self.run_command('rollback')
+        self.assertEqual(os.readlink(self.base / 'current'), 'releases/first')
+        self.assertEqual(installer.Installation(self.root).manifest('first')['release'], 'first')
+        (legacy / 'ferese').write_bytes(b'corrupt')
+        with self.assertRaisesRegex(ValueError, 'Checksum mismatch'):
+            installer.Installation(self.root).manifest('first')
+
+    def test_new_bundle_requires_appearance_wallpapers(self):
+        incomplete = Path(self.temporary.name) / 'incomplete'
+        shutil.copytree(self.bundles[0], incomplete)
+        self.without_appearance_wallpapers(incomplete)
+        result = self.run_command('install', incomplete, success=False)
+        self.assertIn('Bundle is incomplete', result.stderr)
+        self.assertFalse((self.base / 'current').exists())
+
     def test_fresh_upgrade_and_rollback_restore_all_integration(self):
         self.install()
         first = [(self.root / path).read_bytes() for path in (PORTAL, UNIT, DESKTOP)]