feat: update ui-settings to use dark/light theme values

- Change UITHEME_DEFAULT from 'polkadot'/'substrate' to 'light'
- Update UITHEMES options to use 'dark'/'light' values
- Update ICONS to use 'pezkuwi'/'bizinikiwi' branding
- Add isPezkuwi check for domain detection
- Bump ui-settings version to 3.16.9

packages/ui-settings/package.json

@@ -18,7 +18,7 @@
     "./packageDetect.cjs"
   ],
   "type": "module",
-  "version": "3.16.8",
+  "version": "3.16.9",
   "main": "index.js",
   "dependencies": {
     "@pezkuwi/networks": "^14.0.5",