fix: Ralph panel toggle icon no longer changes erratically

The toggle icon was confusing because CSS rotation (90deg when expanded)
combined with JS icon swapping caused left arrow → right arrow transitions.

Changes:
- Remove CSS rotation transform from .ralph-toggle
- Use consistent down/up arrows matching Monitor panel convention
- Collapsed: ▼ (down) - click to expand
- Expanded: ▲ (up) - click to collapse

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

src/web/public/styles.css

@@ -592,14 +592,9 @@ body {
 .ralph-toggle {
   color: var(--text-dim);
   font-size: 0.6rem;
-  transition: transform 0.2s;
   flex-shrink: 0;
 }
 
-.ralph-panel:not(.collapsed) .ralph-toggle {
-  transform: rotate(90deg);
-}
-
 /* Hide detail when collapsed */
 .ralph-panel.collapsed .ralph-detail {
   display: none;