Fix double-tap proximity detection

- Double-tap now requires both taps to be within 30 pixels of each other
- Prevents accidental navigation from taps with different fingers
- If second tap is too far away, it starts a new double-tap sequence

This ensures double-tap only works when intentionally tapping the same spot twice.

🤖 Generated with [Claude Code](https://claude.ai/code)

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

index.html

@@ -4247,9 +4247,23 @@
                 const now = Date.now();
                 const timeSinceLastTap = now - lastTapTime;
 
+                // Get current tap location
+                let currentTapLocation = null;
+                if (e.changedTouches && e.changedTouches.length > 0) {
+                    const touch = e.changedTouches[0];
+                    currentTapLocation = { x: touch.clientX, y: touch.clientY };
+                }
+
                 // Check for double-tap (two taps within 300ms at roughly same location)
-                if (timeSinceLastTap < 300 && lastTapLocation && pendingDestination) {
-                    // Double-tap detected - show navigation dialog
+                if (timeSinceLastTap < 300 && lastTapLocation && currentTapLocation && pendingDestination) {
+                    // Calculate distance between taps
+                    const dx = currentTapLocation.x - lastTapLocation.x;
+                    const dy = currentTapLocation.y - lastTapLocation.y;
+                    const distance = Math.sqrt(dx * dx + dy * dy);
+
+                    // Only trigger if taps are within 30 pixels of each other
+                    if (distance < 30) {
+                        // Double-tap detected at same location - show navigation dialog
                         e.preventDefault();
                         e.stopPropagation();
 
@@ -4261,12 +4275,14 @@
                         lastTapTime = 0; // Reset to prevent triple tap
                         lastTapLocation = null;
                     } else {
-                    // Store this tap for double-tap detection
+                        // Taps too far apart - treat as new first tap
                         lastTapTime = now;
-                    if (e.touches.length === 0 && e.changedTouches.length > 0) {
-                        const touch = e.changedTouches[0];
-                        lastTapLocation = { x: touch.clientX, y: touch.clientY };
+                        lastTapLocation = currentTapLocation;
                     }
+                } else {
+                    // Store this tap for double-tap detection
+                    lastTapTime = now;
+                    lastTapLocation = currentTapLocation;
                 }
 
                 if (isPressing) {