Badge DnD rework: fix duplicate/disappearing badges, add visual feedback

Fix slot 0 drag bug ('0' is falsy), prevent badge duplication from stale
props fallback in InfoStand, add sparse slot support, fix race condition
with pending server updates. Add drag preview, glow animations, drop
settle effect, and remove-badge indicator overlay.

tailwind.config.js

@@ -102,6 +102,25 @@ module.exports = {
             dropShadow: {
                 'hover': '2px 2px 0 rgba(0,0,0,0.8)'
             },
+            keyframes: {
+                pulseGlow: {
+                    '0%, 100%': { boxShadow: '0 0 6px rgba(59,130,246,0.3)' },
+                    '50%': { boxShadow: '0 0 14px rgba(59,130,246,0.6)' },
+                },
+                pulseGlowRed: {
+                    '0%, 100%': { boxShadow: '0 0 6px rgba(239,68,68,0.3)' },
+                    '50%': { boxShadow: '0 0 14px rgba(239,68,68,0.6)' },
+                },
+                dropSettle: {
+                    '0%': { transform: 'scale(1.15)' },
+                    '100%': { transform: 'scale(1)' },
+                },
+            },
+            animation: {
+                'pulse-glow': 'pulseGlow 1.2s ease-in-out infinite',
+                'pulse-glow-red': 'pulseGlowRed 1.2s ease-in-out infinite',
+                'drop-settle': 'dropSettle 0.3s ease-out',
+            },
         },
     },
     safelist: [
@@ -144,7 +163,10 @@ module.exports = {
         'grid-rows-11',
         'grid-rows-12',
         'justify-end',
-        'items-end'
+        'items-end',
+        'animate-pulse-glow',
+        'animate-pulse-glow-red',
+        'animate-drop-settle'
     ],
     darkMode: 'class',
     variants: {