Release v2.13.1 - Help modal and navigation improvements

- Add help modal system with keyboard shortcuts reference
- Add Main Dashboard button in navigation bar
- Make settings modal accessible from all dashboards
- Dashboard CSS improvements and consistency fixes

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

static/css/adsb_dashboard.css

@@ -73,7 +73,7 @@ body {
     }
 }
 
-/* Header - Mobile first */
+/* Header */
 .header {
     position: relative;
     z-index: 10;
@@ -83,15 +83,14 @@ body {
     display: flex;
     justify-content: space-between;
     align-items: center;
-    flex-wrap: wrap;
-    gap: 8px;
+    flex-wrap: nowrap;
+    gap: 12px;
     min-height: 52px;
 }
 
 @media (min-width: 768px) {
     .header {
         padding: 12px 20px;
-        flex-wrap: nowrap;
     }
 }
 
@@ -128,14 +127,52 @@ body {
         letter-spacing: 2px;
     }
 }
-}
 
 .status-bar {
     display: flex;
-    gap: 20px;
+    gap: 12px;
     align-items: center;
     font-family: var(--font-mono);
     font-size: 11px;
+    flex-wrap: nowrap;
+}
+
+.agent-selector-compact {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+}
+
+.agent-selector-compact .agent-select-sm {
+    padding: 4px 8px;
+    background: var(--bg-card);
+    border: 1px solid var(--border-color);
+    border-radius: 4px;
+    color: var(--text-primary);
+    font-size: 11px;
+    font-family: var(--font-mono);
+}
+
+.agent-selector-compact .agent-status-dot {
+    width: 8px;
+    height: 8px;
+    border-radius: 50%;
+    background: var(--accent-green);
+    box-shadow: 0 0 6px var(--accent-green);
+}
+
+.agent-selector-compact .agent-status-dot.offline {
+    background: var(--accent-red);
+    box-shadow: 0 0 6px var(--accent-red);
+}
+
+.agent-selector-compact .show-all-label {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    font-size: 11px;
+    color: var(--text-secondary);
+    cursor: pointer;
 }
 
 .status-dot {
@@ -174,15 +211,15 @@ body {
 }
 
 /* Main dashboard grid - Mobile first */
-/* Header ~55px + Stats strip ~55px = ~110px, using 115px for safety */
+/* Header ~52px + Nav 44px + Stats strip ~55px = ~151px, using 160px for safety */
 .dashboard {
     position: relative;
     z-index: 10;
     display: flex;
     flex-direction: column;
     gap: 0;
-    height: calc(100dvh - 115px);
-    height: calc(100vh - 115px); /* Fallback */
+    height: calc(100dvh - 160px);
+    height: calc(100vh - 160px); /* Fallback */
     min-height: 400px;
 }
 
@@ -218,7 +255,7 @@ body {
 @media (min-width: 1024px) {
     .acars-sidebar {
         display: flex;
-        max-height: calc(100dvh - 115px);
+        max-height: calc(100dvh - 160px);
     }
 }
 
@@ -1219,7 +1256,7 @@ body {
         display: flex !important;
         flex-direction: column !important;
         height: auto !important;
-        min-height: calc(100dvh - 115px);
+        min-height: calc(100dvh - 160px);
         overflow-y: auto !important;
         overflow-x: hidden;
         -webkit-overflow-scrolling: touch;
@@ -1288,12 +1325,6 @@ body {
         padding: 6px 8px;
     }
 
-    /* Status bar - compact on mobile */
-    .status-bar {
-        flex-wrap: wrap;
-        gap: 6px;
-    }
-
     /* Strip time smaller on mobile */
     .strip-time {
         font-size: 10px;