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/widgets/fai_error_box.dart

@@ -20,15 +20,18 @@ class FaiErrorBox extends StatefulWidget {
   /// monospace, selectable, multi-line. Ignored when [error] is
   /// supplied.
   final String text;
+
   /// When true, the box border + foreground colour come from the
   /// error palette. False renders neutral chrome — useful for
   /// success / informational copy that still wants the copy
   /// button.
   final bool isError;
+
   /// Optional max-height before the content scrolls inside the
   /// box. Falls back to no constraint when null so short
   /// messages don't get a useless scrollbar.
   final double? maxHeight;
+
   /// When non-null, the box renders the [friendlyError] mapping
   /// of this error: a one-line headline, a recovery-hint line
   /// (when one applies), and the verbatim original message
@@ -45,9 +48,9 @@ class FaiErrorBox extends StatefulWidget {
     this.maxHeight,
     this.error,
   }) : assert(
-          text != '' || error != null,
-          'FaiErrorBox needs either text or error',
-        );
+         text != '' || error != null,
+         'FaiErrorBox needs either text or error',
+       );
 
   @override
   State<FaiErrorBox> createState() => _FaiErrorBoxState();
@@ -139,15 +142,15 @@ class _FaiErrorBoxState extends State<FaiErrorBox> {
                   mainAxisSize: MainAxisSize.min,
                   children: [
                     Icon(
-                      _detailExpanded
-                          ? Icons.expand_less
-                          : Icons.expand_more,
+                      _detailExpanded ? Icons.expand_less : Icons.expand_more,
                       size: 14,
                       color: theme.colorScheme.onSurfaceVariant,
                     ),
                     const SizedBox(width: 4),
                     Text(
-                      _detailExpanded ? l.buttonHideDetails : l.buttonShowDetails,
+                      _detailExpanded
+                          ? l.buttonHideDetails
+                          : l.buttonShowDetails,
                       style: theme.textTheme.bodySmall?.copyWith(
                         color: theme.colorScheme.onSurfaceVariant,
                       ),