fix(ux): improve microinteractions across the app

1. Nav-item tap: smooth scale transition instead of abrupt snap
2. Custom toggle switch: iOS-style toggle replaces native checkboxes
3. Focus-visible: outline on cards, buttons, FABs for keyboard users
4. Empty-state: gentle fade-in animation
5. Toast icons: SVG icons for success/danger/warning types
6. Swipe haptic: vibrate(15) fires at threshold during touchmove

public/pages/tasks.js

@@ -730,6 +730,7 @@ function wireSwipeGestures(container) {
     let startX = 0, startY = 0;
     let dx = 0;
     let locked = false;    // false = unentschieden, 'swipe' | 'scroll'
+    let thresholdHit = false; // Haptic-Feedback am Threshold nur einmal
     const card = row.querySelector('.task-card');
     if (!card) return;
 
@@ -749,6 +750,7 @@ function wireSwipeGestures(container) {
       startY = e.touches[0].clientY;
       dx     = 0;
       locked = false;
+      thresholdHit = false;
       card.style.transition = '';
     }, { passive: true });
 
@@ -794,6 +796,12 @@ function wireSwipeGestures(container) {
         row.querySelector('.swipe-reveal--edit').style.opacity = String(progress);
         row.querySelector('.swipe-reveal--done').style.opacity = '0';
       }
+
+      // Haptic-Feedback beim Erreichen des Schwellwerts
+      if (!thresholdHit && Math.abs(dx) >= SWIPE_THRESHOLD) {
+        thresholdHit = true;
+        vibrate(15);
+      }
     }, { passive: false });
 
     row.addEventListener('touchend', async () => {