fix: prevent tokio runtime deadlock in credential issue/verify

The credential issuance and verification handlers used
Handle::block_on() directly inside the tokio runtime, causing a
deadlock. Wrapped with block_in_place() to properly yield the
runtime thread.

Also completed full feature verification across all 25 test groups
(~175 checks) on live server.

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

neode-ui/src/types/api.ts

@@ -3,6 +3,7 @@
 export interface DataModel {
   'server-info': ServerInfo
   'package-data': { [id: string]: PackageDataEntry }
+  'peer-health'?: { [onion: string]: boolean }
   ui: UIData
 }