refactor(lists): route follows + hashtag-prefs subs through SubscriptionManager (P4)

The two feed-driving list subscriptions (kind-30000 follows, kind-30015/30005
hashtag prefs) now go through the L1 SubscriptionManager instead of the global
relaySubscriptionService singleton: centralized dedup + reconnect re-issue (the
lists self-heal after a relay drop). Handles are stored and closed on teardown;
relaySubscriptionService is retained as the manager-less fallback.

Verified: subscriptions-manager/-feed + hashtag-preferences suites pass (32);
flaky multi-relay harness still all-PASS; pool-access lint clean.

Co-Authored-By: Claude Opus 4.8 <[email protected]>

js/services/hashtagPreferencesService.js

@@ -325,6 +325,14 @@ class HashtagPreferencesService {
   }
 
   stopHashtagPreferencesSubscription() {
+    if (this.subscriptionHandle) {
+      try {
+        this.subscriptionHandle.close();
+      } catch (error) {
+        devLogger.warn(`${LOG_PREFIX} Failed to close hashtag subscription handle`, error);
+      }
+      this.subscriptionHandle = null;
+    }
     if (this.subscriptionKey) {
       relaySubscriptionService.stopSubscription(this.subscriptionKey, "reset");
       this.subscriptionKey = null;
@@ -353,6 +361,23 @@ class HashtagPreferencesService {
     const key = `hashtags:${normalized}`;
     this.subscriptionKey = key;
 
+    // Route through the L1 SubscriptionManager when available (dedup + reconnect
+    // re-issue); fall back to relaySubscriptionService in manager-less envs.
+    const manager =
+      typeof nostrClient.getSubscriptionManager === "function"
+        ? nostrClient.getSubscriptionManager()
+        : null;
+    if (manager) {
+      this.subscriptionHandle = manager.subscribe({
+        key,
+        relays,
+        filters,
+        label: "hashtag-preferences",
+        onEvent: (event) => this.handleHashtagPreferencesEvent(event),
+      });
+      return this.subscriptionHandle;
+    }
+
     return relaySubscriptionService.ensureSubscription({
       key,
       pool: nostrClient.pool,

js/subscriptions.js

@@ -851,6 +851,14 @@ class SubscriptionsManager {
   }
 
   stopSubscriptionListSubscription() {
+    if (this.subscriptionHandle) {
+      try {
+        this.subscriptionHandle.close();
+      } catch (error) {
+        devLogger.warn("[SubscriptionsManager] Failed to close subscription handle", error);
+      }
+      this.subscriptionHandle = null;
+    }
     if (this.subscriptionKey) {
       relaySubscriptionService.stopSubscription(this.subscriptionKey, "reset");
       this.subscriptionKey = null;
@@ -874,6 +882,24 @@ class SubscriptionsManager {
       },
     ];
 
+    // Route through the L1 SubscriptionManager when available: centralized
+    // dedup + reconnect re-issue (so the follows list self-heals after a relay
+    // drop). Falls back to relaySubscriptionService in manager-less envs.
+    const manager =
+      typeof nostrClient.getSubscriptionManager === "function"
+        ? nostrClient.getSubscriptionManager()
+        : null;
+    if (manager) {
+      this.subscriptionHandle = manager.subscribe({
+        key,
+        relays,
+        filters,
+        label: "subscription-list",
+        onEvent: (event) => this.handleSubscriptionListEvent(event),
+      });
+      return this.subscriptionHandle;
+    }
+
     return relaySubscriptionService.ensureSubscription({
       key,
       pool: nostrClient.pool,