Strip all box-shadow/text-shadow from hover states inside ascii-frame-outer

These non-composited properties force CPU repaints of the surrounding
paint region (the section itself) every time hover enters or exits.
With the fixed overlay (body::before scanline), each such repaint
requires the compositor to re-blend the layer, visible as a blink.

Removed from dashboard.css:
- btn/button/btn-base:hover: box-shadow + text-shadow
- th:hover: text-shadow
- ticket-link:hover: text-shadow
- pagination button:hover: box-shadow + transform + transition:all
- ticket-card-row:hover: box-shadow + transition:all -> background only
- .btn ripple rule: transition:all -> specific properties
- ascii-frame-outer: removed will-change/translateZ (GPU upload worse)

Removed from ticket.css:
- metadata-select:hover: box-shadow; transition:all -> border-color
- comment:hover: box-shadow
- btn:hover: box-shadow
- mention:hover: text-shadow

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

assets/css/ticket.css

@@ -262,12 +262,11 @@
     color: var(--terminal-green);
     font-family: var(--font-mono);
     cursor: pointer;
-    transition: all 0.2s ease;
+    transition: border-color 0.2s ease;
 }
 
 .metadata-select:hover {
     border-color: var(--terminal-amber);
-    box-shadow: var(--glow-amber);
 }
 
 .metadata-select:focus {
@@ -564,7 +563,6 @@ textarea.editable {
 }
 
 .btn:hover {
-    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
 }
 
 /* Comments Section - TERMINAL STYLE */
@@ -646,7 +644,6 @@ textarea.editable {
 .comment:hover {
     border-color: var(--terminal-amber);
     background: linear-gradient(135deg, var(--bg-primary) 0%, rgba(255, 176, 0, 0.03) 100%);
-    box-shadow: 0 0 15px rgba(0, 255, 65, 0.1);
 }
 
 .comment:hover::before,
@@ -1790,7 +1787,6 @@ body.dark-mode .editable {
 
 .mention:hover {
     background: rgba(0, 255, 255, 0.2);
-    text-shadow: 0 0 5px var(--terminal-cyan);
 }
 
 .mention::before {