Refactor log view to eliminate flickering during refresh

- Use atomic update pattern in backend: collect logs into temp variable
  before replacing outputs (prevents empty state flash)
- Remove per-line x-effect directives that caused 4000+ reactive
  evaluations on every update
- Replace inline Alpine.js class bindings with CSS utility classes
- Use single $watch and morph.updated hook instead of renderTrigger
- Remove HTML entity decode cache (no longer needed)
- Fix search highlight padding that caused text shifting

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

resources/css/utilities.css

@@ -301,5 +301,22 @@
 
 /* Search highlight styling for logs */
 @utility log-highlight {
-    @apply bg-warning/40 dark:bg-warning/30 rounded-sm px-0.5;
+    @apply bg-warning/40 dark:bg-warning/30;
+}
+
+/* Log level color classes */
+@utility log-error {
+    @apply bg-red-500/10 dark:bg-red-500/15;
+}
+
+@utility log-warning {
+    @apply bg-yellow-500/10 dark:bg-yellow-500/15;
+}
+
+@utility log-debug {
+    @apply bg-purple-500/10 dark:bg-purple-500/15;
+}
+
+@utility log-info {
+    @apply bg-blue-500/10 dark:bg-blue-500/15;
 }