Fix ACARS toggle button icon direction and positioning

- Fix checkAcarsTools error by removing orphaned function call
- Change toggle icon from left arrow to right arrow (indicates collapse direction)
- Fix button positioning to use left edge instead of right edge
- Button now correctly appears on left side of ACARS panel (bordering map)
- Both index.html and adsb_dashboard now behave consistently

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

static/css/adsb_dashboard.css

@@ -211,9 +211,9 @@ body {
 
 .acars-collapse-btn {
     position: absolute;
-    right: 0;
+    left: 0;
     top: 50%;
-    transform: translateY(-50%);
+    transform: translateX(-100%) translateY(-50%);
     width: 24px;
     height: 80px;
     background: var(--bg-card);
@@ -228,14 +228,10 @@ body {
     justify-content: center;
     gap: 6px;
     padding: 8px 0;
-    transition: background 0.2s, right 0.3s ease;
+    transition: background 0.2s;
     z-index: 100;
 }
 
-.acars-sidebar.collapsed .acars-collapse-btn {
-    right: 100%;
-}
-
 .acars-collapse-btn:hover {
     background: rgba(74, 158, 255, 0.2);
 }