a11y: Touch-Target System mit Token-basierter Sizing (Redesign Phase E)

- Neue Tokens: --target-sm (32px), --target-md (40px), --target-lg (48px)
- Globale min-height:44px Regel aus reset.css entfernt
- Alle 28 min-height:unset Overrides eliminiert
- Strategy A: Buttons, Nav-Items, Inputs → 48px mobile, 40px desktop
- Strategy B: Kleine Elemente (Checkboxen, Swatches, Delete-Buttons)
  → ::before Pseudo-Element expandiert Touch-Area auf 48×48px

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

public/styles/budget.css

@@ -259,7 +259,13 @@
   justify-content: center;
   opacity: 0;
   transition: opacity var(--transition-fast), color var(--transition-fast);
-  min-height: unset;
+  position: relative;
+}
+
+.budget-entry__delete::before {
+  content: '';
+  position: absolute;
+  inset: -10px;
 }
 
 .budget-entry:hover .budget-entry__delete {
@@ -308,7 +314,7 @@
   background: none;
   color: var(--color-text-secondary);
   transition: all var(--transition-fast);
-  min-height: unset;
+  min-height: var(--target-lg);
 }
 
 .amount-type-btn--income.amount-type-btn--active {