feat: wait for EOSE before rendering messages to prevent scroll jumping

Message Loading Improvements:
- Use RxJS Subject to track EOSE (End Of Stored Events)
- Use skipUntil operator to delay timeline emissions until EOSE received
- Prevents scroll position jumping during initial message load
- Messages still update reactively after initial EOSE

NIP-29 Adapter:
- Create eoseSubject to track EOSE state
- Emit from subject when EOSE string received from relay subscription
- Apply skipUntil(eoseSubject) to eventStore.timeline() observable

NIP-C7 Adapter:
- Add relay subscription to track EOSE (was missing)
- Use same EOSE tracking pattern as NIP-29
- Apply skipUntil to prevent premature timeline emissions

Benefits:
- Smooth initial load experience without scroll jumping
- All messages appear together after EOSE
- Maintains reactive updates for new messages
- Consistent behavior across both chat protocols

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/lib/chat/adapters/nip-29-adapter.ts

@@ -1,5 +1,5 @@
-import { Observable } from "rxjs";
-import { map, first } from "rxjs/operators";
+import { Observable, Subject } from "rxjs";
+import { map, first, skipUntil } from "rxjs/operators";
 import type { Filter } from "nostr-tools";
 import { ChatProtocolAdapter } from "./base-adapter";
 import type {
@@ -292,6 +292,9 @@ export class Nip29Adapter extends ChatProtocolAdapter {
       filter.since = options.after;
     }
 
+    // Create a subject to track EOSE
+    const eoseSubject = new Subject<void>();
+
     // Start a persistent subscription to the group relay
     // This will feed new messages into the EventStore in real-time
     pool
@@ -303,6 +306,8 @@ export class Nip29Adapter extends ChatProtocolAdapter {
           if (typeof response === "string") {
             // EOSE received
             console.log("[NIP-29] EOSE received for messages");
+            eoseSubject.next();
+            eoseSubject.complete();
           } else {
             // Event received
             console.log(
@@ -313,7 +318,9 @@ export class Nip29Adapter extends ChatProtocolAdapter {
       });
 
     // Return observable from EventStore which will update automatically
+    // Wait for EOSE before emitting to prevent scroll jumping during initial load
     return eventStore.timeline(filter).pipe(
+      skipUntil(eoseSubject),
       map((events) => {
         console.log(`[NIP-29] Timeline has ${events.length} messages`);
         return events

src/lib/chat/adapters/nip-c7-adapter.ts

@@ -1,5 +1,5 @@
-import { Observable, firstValueFrom } from "rxjs";
-import { map, first } from "rxjs/operators";
+import { Observable, firstValueFrom, Subject } from "rxjs";
+import { map, first, skipUntil } from "rxjs/operators";
 import { nip19 } from "nostr-tools";
 import type { Filter } from "nostr-tools";
 import { ChatProtocolAdapter } from "./base-adapter";
@@ -156,15 +156,35 @@ export class NipC7Adapter extends ChatProtocolAdapter {
       filter.since = options.after;
     }
 
-    return eventStore
-      .timeline(filter)
-      .pipe(
-        map((events) =>
-          events
-            .map((event) => this.eventToMessage(event, conversation.id))
-            .sort((a, b) => a.timestamp - b.timestamp),
-        ),
-      );
+    // Create a subject to track EOSE
+    const eoseSubject = new Subject<void>();
+
+    // Start subscription to populate EventStore and track EOSE
+    pool
+      .subscription([], [filter], {
+        eventStore, // Automatically add to store
+      })
+      .subscribe({
+        next: (response) => {
+          if (typeof response === "string") {
+            // EOSE received
+            console.log("[NIP-C7] EOSE received for messages");
+            eoseSubject.next();
+            eoseSubject.complete();
+          }
+        },
+      });
+
+    // Return observable from EventStore
+    // Wait for EOSE before emitting to prevent scroll jumping during initial load
+    return eventStore.timeline(filter).pipe(
+      skipUntil(eoseSubject),
+      map((events) =>
+        events
+          .map((event) => this.eventToMessage(event, conversation.id))
+          .sort((a, b) => a.timestamp - b.timestamp),
+      ),
+    );
   }
 
   /**