[feat] update navigation mode default to legacy and improve display name (#5183)

- Change defaultsByInstallVersion from 'standard' to 'legacy' for version 1.25.0
- Update legacy navigation display name from 'Left-Click Pan (Legacy)' to 'Drag Navigation'
- Maintains both navigation systems over long term while improving UX clarity

Author: christian-byrne

src/constants/coreSettings.ts

@@ -790,11 +790,11 @@ export const CORE_SETTINGS: SettingParams[] = [
     type: 'combo',
     options: [
       { value: 'standard', text: 'Standard (New)' },
-      { value: 'legacy', text: 'Left-Click Pan (Legacy)' }
+      { value: 'legacy', text: 'Drag Navigation' }
     ],
     versionAdded: '1.25.0',
     defaultsByInstallVersion: {
-      '1.25.0': 'standard'
+      '1.25.0': 'legacy'
     }
   },
   {