fix: ensure hashtag preferences load on login

When a user logs in, `profileCache` emits a `profileChanged` event. Previously, `HashtagPreferencesService` only reset its state on this event, failing to fetch the new user's preferences. This commit updates the subscription handler to call `load(pubkey)` when a new profile is set, ensuring interests and disinterests are reliably synchronized.

js/services/hashtagPreferencesService.js

@@ -250,6 +250,9 @@ class HashtagPreferencesService {
     profileCache.subscribe((event, detail) => {
       if (event === "profileChanged") {
         this.reset();
+        if (detail.pubkey) {
+          this.load(detail.pubkey);
+        }
       } else if (event === "runtimeCleared" && detail.pubkey === this.activePubkey) {
         this.reset();
         if (this.activePubkey) {