fix(nostr): implement missing resolveEventDTag in NostrClient

Added the `resolveEventDTag` method to the `NostrClient` class in `js/nostr/client.js`. This method was referenced in `editVideo` and `hydrateVideoHistory` but was missing from the implementation, causing `TypeError` in tests. The implementation delegates to `getDTagValueFromTags` from `js/nostr/nip71.js`.

Co-authored-by: PR0M3TH3AN <[email protected]>

js/nostr/client.js

@@ -927,6 +927,18 @@ export class NostrClient {
     return this.connectionManager.makeCountUnsupportedError(relayUrl);
   }
 
+  resolveEventDTag(event, fallbackEvent = null) {
+    if (event && event.tags) {
+      const dTag = getDTagValueFromTags(event.tags);
+      if (dTag) return dTag;
+    }
+    if (fallbackEvent && fallbackEvent.tags) {
+      const dTag = getDTagValueFromTags(fallbackEvent.tags);
+      if (dTag) return dTag;
+    }
+    return "";
+  }
+
   applyRootCreatedAt(video) {
     if (!video || typeof video !== "object") return;
     const rootId = video.videoRootId;