Add delivery order badges and optimize list performance

Enhance delivery list UI with sequential order badges and improve scrolling
performance with faster animations for better user experience.

Delivery Order Badge:
- Add 60x60px status-colored square badge showing delivery sequence number
- Position badge to the left of vertical status bar for clear visual hierarchy
- White text (26px, bold) centered in badge
- Automatically displays deliveryIndex + 1 (first delivery = 1, second = 2, etc.)
- Status color matches delivery state (green for completed, gray for pending, etc.)
- 10px border radius for modern appearance

Layout Enhancements:
- Sidebar expanded from 360px to 420px to accommodate order badges
- Vertical centering of row elements for better visual balance
- Maintains optimized spacing: badge (60px) + gap (12px) + bar (6px) + gap (16px) + content
- Full list scrolling restored (removed 4-item limit)

Animation Performance:
- Stagger animation delay reduced by 90% (50ms to 5ms)
- Fast stagger: 30ms to 3ms for ultra-responsive scrolling
- Delivery items appear almost instantly when scrolling
- Total animation time for 20 items: 500ms to 100ms
- Maintains subtle stagger effect while feeling immediate

User Experience Improvements:
- Clear visual indication of delivery order in route
- Faster perceived loading when scrolling through deliveries
- Better readability with larger, prominent order numbers
- Consistent status color coding across badge and accent bar

Generated with Claude Code

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

lib/components/delivery_list_item.dart

@@ -124,9 +124,29 @@ class _DeliveryListItemState extends State<DeliveryListItem>
                   children: [
                     // Main delivery info row
                     Row(
-                      crossAxisAlignment: CrossAxisAlignment.start,
+                      crossAxisAlignment: CrossAxisAlignment.center,
                       children: [
-                        // Left accent bar (taller for better visual balance)
+                        // Order number badge (left of status bar)
+                        Container(
+                          width: 60,
+                          height: 60,
+                          decoration: BoxDecoration(
+                            color: statusColor,
+                            borderRadius: BorderRadius.circular(10),
+                          ),
+                          child: Center(
+                            child: Text(
+                              '${widget.delivery.deliveryIndex + 1}',
+                              style: const TextStyle(
+                                color: Colors.white,
+                                fontSize: 26,
+                                fontWeight: FontWeight.w700,
+                              ),
+                            ),
+                          ),
+                        ),
+                        const SizedBox(width: 12),
+                        // Left accent bar (vertical status bar)
                         Container(
                           width: 6,
                           height: 80,