feat(fonts): default UI font back to Josefin Sans

Reverts the Inter default introduced in 2.7.0 — Josefin Sans (Light, w300) is
the default UI face again. Inter stays bundled and selectable in Settings →
Appearance; JetBrains Mono remains the default monospace with Fira Mono
selectable. Flips clideUiFamily/default weight, the picker's default + option
order, and the licenses.yaml purpose notes.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lib/builtin/theme_picker/src/extension.dart

@@ -64,10 +64,10 @@ class ThemePickerExtension extends ClideExtension {
                 kind: SettingsFieldKind.select,
                 label: 'UI font',
                 help: 'Typeface for the app interface; applies live.',
-                defaultValue: 'Inter',
+                defaultValue: 'JosefinSans',
                 options: [
-                  SettingsOption(value: 'Inter', label: 'Inter'),
                   SettingsOption(value: 'JosefinSans', label: 'Josefin Sans'),
+                  SettingsOption(value: 'Inter', label: 'Inter'),
                 ],
               ),
               SettingsField(