Fix ascii-frame-outer blink: remove scanline GPU layer and remaining repaint triggers

- Remove body::before scanline animation (transform: translateY promoted it to a
  GPU compositing layer; CPU repaints from hover states required compositor re-blend,
  causing one-frame blink at compositor sync boundary)
- Remove text-shadow and transform: translateY(-2px) from .btn-primary:hover/.create-ticket:hover
- Scope .btn-primary transition from 'all' to specific composited properties
- Remove box-shadow: inset from .banner-toggle:hover

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

assets/css/dashboard.css

@@ -117,16 +117,6 @@ body::before {
     );
     pointer-events: none;
     z-index: var(--z-overlay);
-    animation: scanline 8s linear infinite;
-}
-
-@keyframes scanline {
-    0% {
-        transform: translateY(0);
-    }
-    100% {
-        transform: translateY(4px);
-    }
 }
 
 /* Screen Flicker Effect */
@@ -1676,9 +1666,8 @@ button:active {
     font-weight: bold;
     font-family: var(--font-mono);
     text-transform: uppercase;
-    transition: all 0.3s ease;
+    transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
     margin-right: 3.75rem;
-    text-shadow: var(--glow-amber);
 }
 
 .btn-primary::before,
@@ -1696,8 +1685,6 @@ button:active {
     background: rgba(255, 176, 0, 0.1);
     color: var(--terminal-green);
     border-color: var(--terminal-green);
-    text-shadow: var(--glow-green);
-    transform: translateY(-2px);
 }
 
 /* ===== RESPONSIVE TICKET CARDS - Hidden on desktop (1400px+) ===== */
@@ -2314,7 +2301,6 @@ input[type="checkbox"]:checked {
 
 .banner-toggle:hover {
     background: var(--hover-bg);
-    box-shadow: inset 0 0 20px rgba(255, 176, 0, 0.2);
 }
 
 .toggle-icon {