feat: Refactor onboarding experience and personal info pages

- Updated ExperiencePage to include subtitles in ExperienceSectionTitle.
- Modified ExperienceSectionTitle widget to accept an optional subtitle parameter.
- Refactored PersonalInfoPage to improve imports and structure.
- Removed unused PersonalInfoContent and PersonalInfoForm widgets.
- Introduced new widgets: EditableField, FieldLabel, ReadOnlyField, TappableRow, and LanguageSelector for better modularity.
- Added AccountCard and SecurityNotice widgets for bank account section.
- Enhanced SaveButton to utilize UiButton for consistency.

apps/mobile/packages/design_system/lib/src/ui_typography.dart

@@ -264,6 +264,16 @@ class UiTypography {
     color: UiColors.textPrimary,
   );
 
+  /// Title Uppercase 2 Bold - Font: Instrument Sans, Size: 14, Height: 1.5, Spacing: 0.7 (#121826)
+  /// Used for section headers and important labels.
+  static final TextStyle titleUppercase2b = _primaryBase.copyWith(
+    fontWeight: FontWeight.w700,
+    fontSize: 14,
+    height: 1.5,
+    letterSpacing: 0.4,
+    color: UiColors.textPrimary,
+  );
+
   /// Title Uppercase 3 Medium - Font: Instrument Sans, Size: 12, Height: 1.5, Spacing: 1.5 (#121826)
   static final TextStyle titleUppercase3m = _primaryBase.copyWith(
     fontWeight: FontWeight.w500,