Restore visual effects using GPU-safe techniques (no repaint triggers)

Rules: transform/opacity = GPU composited (fine). box-shadow/text-shadow on
hover = CPU repaint (removed). Static box-shadow/text-shadow = painted once (fine).

- Buttons (.btn, .btn-base, button, .btn-primary): add will-change:transform
  for pre-promotion, add transform:translateY(-1px) on hover (GPU, no repaint),
  scope transition to include transform, remove box-shadow/text-shadow from hover
- Stat cards: add will-change:transform, add transform:translateY(-2px) on hover
- Priority badges: replace filter:blur(6px) ::after pseudo-element (permanent GPU
  layer per badge, ~20 on screen at once) with static box-shadow:0 0 6px currentColor
  on the badge itself — painted once, never changes, zero compositor overhead
- Links: replace opacity-transition ::after underline (lazy GPU layer creation on
  hover) with text-decoration:underline on hover (pure CPU paint, no GPU layer)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

assets/css/dashboard.css

@@ -251,11 +251,14 @@ h1, h2, h3 {
     text-shadow: 0 0 2px currentColor, 0 0 4px currentColor;
 }
 
-/* Enhanced link hover with underline animation */
+/* Link hover — text-decoration (no opacity pseudo-element, no GPU layer creation) */
 a:not(.btn) {
-    position: relative;
     text-decoration: none;
 }
+a:not(.btn):hover {
+    text-decoration: underline;
+    text-underline-offset: 3px;
+}
 
 a:not(.btn)::after {
     content: '';
@@ -349,20 +352,9 @@ tbody tr {
     51%, 100% { opacity: 0; }
 }
 
-/* Neon glow effect for priority badges */
+/* Neon glow effect for priority badges — static box-shadow (no filter:blur GPU layer) */
 .priority-badge {
-    position: relative;
-}
-
-.priority-badge::after {
-    content: '';
-    position: absolute;
-    inset: -2px;
-    border-radius: inherit;
-    background: inherit;
-    filter: blur(6px);
-    opacity: 0.4;
-    z-index: -1;
+    box-shadow: 0 0 6px currentColor;
 }
 
 /* Smooth scrollbar styling */
@@ -1605,7 +1597,8 @@ button {
     text-transform: uppercase;
     font-weight: bold;
     position: relative;
-    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease, text-shadow 0.2s ease;
+    will-change: transform;
+    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
 }
 
 .btn::before,
@@ -1626,13 +1619,13 @@ button:hover {
     background: rgba(0, 255, 65, 0.15);
     color: var(--terminal-amber);
     border-color: var(--terminal-amber);
+    transform: translateY(-1px);
 }
 
 .btn:active,
 .btn-base:active,
 button:active {
     transform: translateY(0);
-    box-shadow: var(--glow-green-intense);
 }
 
 @keyframes pulse-glow-box {
@@ -1663,7 +1656,8 @@ button:active {
     font-weight: bold;
     font-family: var(--font-mono);
     text-transform: uppercase;
-    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
+    will-change: transform;
+    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
     margin-right: 3.75rem;
 }
 
@@ -1682,6 +1676,7 @@ button:active {
     background: rgba(255, 176, 0, 0.1);
     color: var(--terminal-green);
     border-color: var(--terminal-green);
+    transform: translateY(-1px);
 }
 
 /* ===== RESPONSIVE TICKET CARDS - Hidden on desktop (1400px+) ===== */
@@ -4320,7 +4315,8 @@ tr:hover .quick-actions {
     padding: 1rem;
     background: linear-gradient(135deg, var(--bg-secondary) 0%, rgba(0, 255, 65, 0.03) 100%);
     border: 2px solid var(--terminal-green);
-    transition: border-color 0.2s ease;
+    will-change: transform;
+    transition: border-color 0.2s ease, transform 0.15s ease;
     position: relative;
     overflow: hidden;
 }
@@ -4338,6 +4334,7 @@ tr:hover .quick-actions {
 
 .stat-card:hover {
     border-color: var(--terminal-amber);
+    transform: translateY(-2px);
 }
 
 /* Critical stat card styling */