feat: implement custom responsive gantt chart UI for intern applications widget

app/Filament/Admin/Resources/InternApplications/Widgets/InternGanttChartWidget.php

@@ -132,6 +132,22 @@ class InternGanttChartWidget extends Widget
             $paletteIndex = $intern->id % count($palettes);
             $color = $palettes[$paletteIndex];
 
+            $startMonth = (int) $start->format('n');
+            $endMonth = (int) $end->format('n');
+            $gridStart = $startMonth + 1;
+            $gridEnd = min(14, $endMonth + 2);
+
+            // Background color map based on user's examples
+            $hexColors = [
+                '#2ecaac', // Emerald Teal
+                '#54c6f9', // Sky Blue
+                '#ff6252', // Red Coral
+                '#f59e0b', // Amber
+                '#8b5cf6', // Violet
+            ];
+            $hexColor = $hexColors[$intern->id % count($hexColors)];
+            $isStripes = ($intern->id % 2 === 0);
+
             return [
                 'id' => $intern->id,
                 'name' => $intern->name,
@@ -141,6 +157,10 @@ class InternGanttChartWidget extends Widget
                 'left' => $left,
                 'width' => $width,
                 'color' => $color,
+                'grid_start' => $gridStart,
+                'grid_end' => $gridEnd,
+                'hex_color' => $hexColor,
+                'is_stripes' => $isStripes,
             ];
         });