feat(studio): rich theme picker (presets + custom colour) + editor 0.11.0

Settings dialog's Theme Plugin section is now a grid of
swatched tiles:

- Built-in (none) — falls back to FaiTheme.light/.dark
- One tile per installed studio.theme.* plugin, each
  showing the plugin's primary/secondary/tertiary as
  live colour dots. Tile loads its preview lazily so a
  dozen installed themes don't block the picker.
- Custom — opens a colour-picker dialog with 12 curated
  Material presets + a hex input + live preview. Selecting
  applies ColorScheme.fromSeed for both brightnesses.

main.dart's _pluginThemes parses a 'custom:#RRGGBB' sigil
in the same notifier slot as plugin capability ids, so the
existing persistence + restoration paths cover the custom
case with no new state.

Bumps editor to 0.11.0 (type-checked port connections +
dynamic card width fix + card-height border allowance) and
Studio to 0.58.0.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/data/hub_auth_token.dart

@@ -15,12 +15,10 @@ import 'package:path/path.dart' as p;
 /// based on its own `auth.tokens:` config.
 class HubAuthToken {
   static String _faiHome() {
-    final home = Platform.environment['HOME'] ??
-        Platform.environment['USERPROFILE'];
+    final home =
+        Platform.environment['HOME'] ?? Platform.environment['USERPROFILE'];
     if (home == null || home.isEmpty) {
-      throw StateError(
-        'Cannot resolve home directory (no HOME / USERPROFILE)',
-      );
+      throw StateError('Cannot resolve home directory (no HOME / USERPROFILE)');
     }
     return p.join(home, '.fai');
   }
@@ -79,7 +77,9 @@ class HubAuthToken {
     if ((Platform.isLinux || Platform.isMacOS) && !parentExisted) {
       try {
         await Process.run('chmod', ['700', parent.path]);
-      } catch (_) {/* best-effort */}
+      } catch (_) {
+        /* best-effort */
+      }
     }
     // Write to the temp path with restrictive mode set up
     // BEFORE the rename — the final file is never visible
@@ -88,7 +88,9 @@ class HubAuthToken {
     if (Platform.isLinux || Platform.isMacOS) {
       try {
         await Process.run('chmod', ['600', tmp.path]);
-      } catch (_) {/* best-effort */}
+      } catch (_) {
+        /* best-effort */
+      }
     }
     // Atomic rename: on POSIX, replaces the destination
     // in one syscall. On Windows, Dart's File.rename uses
@@ -105,7 +107,9 @@ class HubAuthToken {
       if (Platform.isLinux || Platform.isMacOS) {
         try {
           await Process.run('chmod', ['600', f.path]);
-        } catch (_) {/* best-effort */}
+        } catch (_) {
+          /* best-effort */
+        }
       }
       await tmp.delete();
     }