fix: dark mode for Live Demo tab + pose_source passthrough

- Convert all Live Demo sidebar panels to dark theme matching rest of UI
- Fix pose_source not reaching LiveDemoTab (was lost in
  convertZoneDataToRestFormat — now passes through from WS message)
- Dark backgrounds, muted text, consistent border opacity throughout
- Estimation Mode badge colors adjusted for dark background contrast

Co-Authored-By: claude-flow <ruv@ruv.net>

ui/services/pose.service.js

@@ -511,6 +511,7 @@ export class PoseService {
       persons: persons,
       zone_summary: zoneSummary,
       processing_time_ms: zoneData.metadata?.processing_time_ms || 0,
+      pose_source: originalMessage.pose_source || zoneData.pose_source || null,
       metadata: {
         mock_data: false,
         source: 'websocket',