Rewrite HAOS integration: target-centric architecture with KC color sensors

- Rewrite integration to target-centric model: each picture target becomes
  a HA device under a server hub with switch, FPS, and status sensors
- Replace KC light entities with color sensors (hex state + RGB attributes)
  for better automation support via WebSocket real-time updates
- Add WebSocket manager for Key Colors color streaming
- Add KC per-stage timing metrics (calc_colors, broadcast) with rolling avg
- Fix KC timing fields missing from API by adding them to Pydantic schema
- Make start/stop processing idempotent to prevent intermittent 404 errors
- Add HAOS localization support (en, ru) using translation_key system
- Rename integration from "WLED Screen Controller" to "LED Screen Controller"
- Remove obsolete select.py (display select) and README.md

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

server/src/wled_controller/static/app.js

@@ -4894,6 +4894,24 @@ function createKCTargetCard(target, sourceMap, patternTemplateMap) {
                         <div class="metric-value">${metrics.errors_count || 0}</div>
                     </div>
                 </div>
+                ${state.timing_total_ms != null ? `
+                <div class="timing-breakdown">
+                    <div class="timing-header">
+                        <div class="metric-label">${t('device.metrics.timing')}</div>
+                        <div class="timing-total"><strong>${state.timing_total_ms}ms</strong></div>
+                    </div>
+                    <div class="timing-bar">
+                        <span class="timing-seg timing-extract" style="flex:${state.timing_calc_colors_ms}" title="calc ${state.timing_calc_colors_ms}ms"></span>
+                        <span class="timing-seg timing-smooth" style="flex:${state.timing_smooth_ms || 0.1}" title="smooth ${state.timing_smooth_ms}ms"></span>
+                        <span class="timing-seg timing-send" style="flex:${state.timing_broadcast_ms}" title="broadcast ${state.timing_broadcast_ms}ms"></span>
+                    </div>
+                    <div class="timing-legend">
+                        <span class="timing-legend-item"><span class="timing-dot timing-extract"></span>calc ${state.timing_calc_colors_ms}ms</span>
+                        <span class="timing-legend-item"><span class="timing-dot timing-smooth"></span>smooth ${state.timing_smooth_ms}ms</span>
+                        <span class="timing-legend-item"><span class="timing-dot timing-send"></span>broadcast ${state.timing_broadcast_ms}ms</span>
+                    </div>
+                </div>
+                ` : ''}
                 ` : ''}
             </div>
             <div class="card-actions">