Replace `settings.activeDid` with `$getActiveIdentity()` API call.
Updates test/prod server warning logic to use active_identity table.
- Add `const activeIdentity = await this.$getActiveIdentity();`
- Update didPrefix extraction for both warning conditions
- Maintain existing warning functionality
✅ TypeScript compilation passes
✅ Linting standards met
✅ Functionality preserved
Part of ActiveDid migration following "One Component + Test Pattern".