Add OpenRGB per-zone LED control with separate/combined modes and zone preview

- Zone picker UI in device add/settings modals with per-zone checkbox selection
- Combined mode: pixels distributed sequentially across zones
- Separate mode: full effect resampled independently to each zone via linear interpolation
- Per-zone LED preview in target cards: one canvas strip per zone with hover overlay labels
- Zone badges on device cards enriched with actual LED counts from OpenRGB API
- Fix stale led_count by using device_led_count discovered at connect time

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/css/cards.css

@@ -443,6 +443,62 @@ body.cs-drag-active .card-drag-handle {
     animation: spin 0.8s linear infinite;
 }
 
+/* OpenRGB zone checkboxes */
+.zone-checkbox-list {
+    display: flex;
+    flex-direction: column;
+    gap: 4px;
+    max-height: 180px;
+    overflow-y: auto;
+    padding: 4px 0;
+}
+.zone-checkbox-list .zone-loading,
+.zone-checkbox-list .zone-error {
+    font-size: 12px;
+    color: var(--text-secondary);
+    padding: 4px 0;
+}
+.zone-checkbox-list .zone-error { color: var(--danger-color, #e53935); }
+.zone-checkbox-item {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+    padding: 4px 6px;
+    border-radius: 4px;
+    cursor: pointer;
+    font-size: 13px;
+    transition: background 0.15s;
+}
+.zone-checkbox-item:hover { background: var(--hover-bg, rgba(255,255,255,0.05)); }
+.zone-checkbox-item input[type="checkbox"] { margin: 0; flex-shrink: 0; }
+.zone-checkbox-item .zone-led-count {
+    margin-left: auto;
+    font-size: 11px;
+    color: var(--text-secondary);
+    white-space: nowrap;
+}
+
+.zone-mode-radios {
+    display: flex;
+    gap: 16px;
+}
+.zone-mode-option {
+    display: flex;
+    align-items: center;
+    gap: 6px;
+    cursor: pointer;
+    font-size: 13px;
+}
+.zone-mode-option input[type="radio"] { margin: 0; }
+
+.zone-badge {
+    font-size: 10px;
+    padding: 1px 5px;
+    border-radius: 3px;
+    background: var(--border-color);
+    font-weight: 600;
+}
+
 .channel-indicator {
     display: inline-flex;
     gap: 2px;
@@ -792,3 +848,42 @@ ul.section-tip li {
     pointer-events: none;
     opacity: 0.8;
 }
+
+/* Per-zone LED preview (OpenRGB separate mode) */
+.led-preview-zones {
+    display: flex;
+    flex-direction: column;
+    gap: 2px;
+}
+
+.led-preview-zone {
+    position: relative;
+}
+
+.led-preview-zone-canvas {
+    display: block;
+    width: 100%;
+    height: 18px;
+    border-radius: 2px;
+    image-rendering: pixelated;
+    background: #111;
+}
+
+.led-preview-zone-label {
+    position: absolute;
+    left: 4px;
+    top: 50%;
+    transform: translateY(-50%);
+    font-size: 0.65rem;
+    font-family: var(--font-mono, monospace);
+    color: #fff;
+    text-shadow: 0 0 3px rgba(0,0,0,0.9), 0 0 6px rgba(0,0,0,0.6);
+    pointer-events: none;
+    opacity: 0;
+    transition: opacity 0.15s;
+    white-space: nowrap;
+}
+
+.led-preview-zones:hover .led-preview-zone-label {
+    opacity: 1;
+}