Add primary display indicator, custom accent color picker, restart script

- Detect primary monitor via Windows EnumDisplayMonitors API and show badge
- Expand accent color picker with 9 presets and custom color input
- Auto-generate hover color for custom accent colors
- Re-render accent swatches on locale change for proper i18n
- Replace restart-server.bat with PowerShell restart-server.ps1

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

media_server/static/css/styles.css

@@ -303,12 +303,12 @@ h1 {
     top: calc(100% + 4px);
     background: var(--bg-secondary);
     border: 1px solid var(--border);
-    border-radius: 8px;
-    padding: 8px;
+    border-radius: 12px;
+    padding: 10px;
     gap: 6px;
     z-index: 100;
     box-shadow: 0 4px 12px rgba(0,0,0,0.3);
-    grid-template-columns: repeat(3, 24px);
+    grid-template-columns: repeat(3, 28px);
 }
 
 .accent-picker-dropdown.open {
@@ -316,8 +316,8 @@ h1 {
 }
 
 .accent-swatch {
-    width: 24px;
-    height: 24px;
+    width: 28px;
+    height: 28px;
     border-radius: 50%;
     border: 2px solid transparent;
     cursor: pointer;
@@ -325,13 +325,57 @@ h1 {
 }
 
 .accent-swatch:hover {
-    transform: scale(1.2);
+    transform: scale(1.15);
 }
 
 .accent-swatch.active {
     border-color: var(--text-primary);
 }
 
+.accent-custom-row {
+    grid-column: 1 / -1;
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 6px 2px 2px;
+    margin-top: 4px;
+    border-top: 1px solid var(--border);
+    cursor: pointer;
+    border-radius: 4px;
+}
+
+.accent-custom-row:hover .accent-custom-label {
+    color: var(--text-primary);
+}
+
+.accent-custom-row.active .accent-custom-swatch {
+    outline: 2px solid var(--text-primary);
+    outline-offset: 1px;
+}
+
+.accent-custom-swatch {
+    width: 20px;
+    height: 20px;
+    border-radius: 4px;
+    flex-shrink: 0;
+}
+
+.accent-custom-label {
+    font-size: 0.75rem;
+    color: var(--text-muted);
+    transition: color 0.15s;
+}
+
+.accent-custom-row input[type="color"] {
+    width: 0;
+    height: 0;
+    padding: 0;
+    border: none;
+    opacity: 0;
+    position: absolute;
+    pointer-events: none;
+}
+
 #locale-select {
     background: var(--bg-tertiary);
     border: 1px solid var(--border);
@@ -1115,6 +1159,20 @@ button:disabled {
             white-space: nowrap;
         }
 
+        .display-primary-badge {
+            display: inline-block;
+            background: var(--accent);
+            color: #fff;
+            font-size: 0.625rem;
+            font-weight: 600;
+            padding: 1px 6px;
+            border-radius: 8px;
+            margin-left: 6px;
+            vertical-align: middle;
+            text-transform: uppercase;
+            letter-spacing: 0.03em;
+        }
+
         .display-monitor-details {
             font-size: 0.75rem;
             color: var(--text-muted);