Standardize UI to design system tokens

Refactor multiple UI components to use design system tokens and primitives. Added new UiIcons (coffee, wifi, xCircle, ban) and typography color getters (primary, accent). Replaced hardcoded paddings, spacings, radii, borderRadius, and icon imports (lucide_icons -> UiIcons) with UiConstants, UiColors, UiTypography and UiIcons, and switched to UiColors.withValues for opacity. Changes apply across authentication, availability, clock_in (and its widgets), commute tracker, lunch break modal, location map placeholder, attendance card, date selector, and related presentation files to improve visual consistency.

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

@@ -237,4 +237,16 @@ class UiIcons {
 
   /// Timer icon
   static const IconData timer = _IconLib.timer;
+
+  /// Coffee icon for breaks
+  static const IconData coffee = _IconLib.coffee;
+
+  /// Wifi icon for NFC check-in
+  static const IconData wifi = _IconLib.wifi;
+
+  /// X Circle icon for no-shows
+  static const IconData xCircle = _IconLib.xCircle;
+
+  /// Ban icon for cancellations
+  static const IconData ban = _IconLib.ban;
 }

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

@@ -579,4 +579,10 @@ extension TypographyColors on TextStyle {
 
   /// Active content color
   TextStyle get activeContentColor => copyWith(color: UiColors.textPrimary);
+
+  /// Primary color
+  TextStyle get primary => copyWith(color: UiColors.primary);
+
+  /// Accent color
+  TextStyle get accent => copyWith(color: UiColors.accent);
 }