fix: Mobile sidebar and ticket page improvements

Dashboard sidebar fixes:
- Added proper styling for sidebar interior on mobile
- Filter groups have touch-friendly labels (44px height)
- Larger checkboxes (22px)
- Full-width apply/clear buttons
- Border separators between filter groups

Ticket page fixes:
- Metadata fields stack vertically on mobile
- Assignment dropdown full-width
- All selects have 48px height and 16px font
- Better spacing throughout
- Sticky header

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

assets/css/dashboard.css

@@ -3951,6 +3951,65 @@ table td:nth-child(4) {
 
     .dashboard-sidebar .sidebar-content {
         display: block;
+        padding-top: 1rem;
+    }
+
+    /* Mobile sidebar interior styling */
+    .dashboard-sidebar .ascii-frame-inner {
+        padding: 1rem !important;
+        border: 2px solid var(--terminal-green) !important;
+        background: var(--bg-secondary) !important;
+    }
+
+    .dashboard-sidebar .ascii-subsection-header {
+        font-size: 1.1rem;
+        margin-bottom: 1rem;
+        padding-bottom: 0.5rem;
+    }
+
+    .dashboard-sidebar .filter-group {
+        margin-bottom: 1.5rem;
+        padding-bottom: 1rem;
+        border-bottom: 1px solid rgba(0, 255, 65, 0.3);
+    }
+
+    .dashboard-sidebar .filter-group:last-of-type {
+        border-bottom: none;
+    }
+
+    .dashboard-sidebar .filter-group h4 {
+        font-size: 0.95rem;
+        margin-bottom: 0.75rem;
+        color: var(--terminal-amber);
+    }
+
+    .dashboard-sidebar .filter-group label {
+        display: flex;
+        align-items: center;
+        padding: 0.75rem 0.5rem;
+        margin: 0.25rem 0;
+        min-height: 44px;
+        font-size: 0.95rem;
+        background: rgba(0, 255, 65, 0.05);
+        border-radius: 4px;
+    }
+
+    .dashboard-sidebar .filter-group label:active {
+        background: rgba(0, 255, 65, 0.15);
+    }
+
+    .dashboard-sidebar .filter-group input[type="checkbox"] {
+        width: 22px;
+        height: 22px;
+        margin-right: 0.75rem;
+        flex-shrink: 0;
+    }
+
+    .dashboard-sidebar .btn {
+        width: 100%;
+        min-height: 48px;
+        margin-top: 0.5rem;
+        font-size: 1rem;
     }
 
     /* Mobile sidebar overlay */