fix: build proper q-tag with relay hint and author pubkey for replies

When sending replies in NIP-29 and NIP-C7 adapters, now build the full
q-tag format per NIP-C7 spec: ["q", eventId, relayUrl, pubkey]

Previously only the event ID was included, making it harder for clients
to fetch the referenced event. Now:
- NIP-29: includes group relay URL and author pubkey
- NIP-C7: includes seen relay hint and author pubkey

https://claude.ai/code/session_01Jy51Ayk57fzaFuuFFm1j1K

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

@@ -459,9 +459,18 @@ export class Nip29Adapter extends ChatProtocolAdapter {
       },
     );
 
-    // Add q-tag for replies (NIP-29 specific, not in blueprint yet)
+    // Add q-tag for replies (per NIP-C7 quote tag format)
+    // Format: ["q", eventId, relayUrl, pubkey]
     if (options?.replyTo) {
-      draft.tags.push(["q", options.replyTo]);
+      // Look up the event to get the author's pubkey for the q-tag
+      const replyEvent = eventStore.getEvent(options.replyTo);
+      if (replyEvent) {
+        // Full q-tag with relay hint and author pubkey
+        draft.tags.push(["q", options.replyTo, relayUrl, replyEvent.pubkey]);
+      } else {
+        // Fallback: at minimum include the relay hint since we know it
+        draft.tags.push(["q", options.replyTo, relayUrl]);
+      }
     }
 
     // Add NIP-92 imeta tags for blob attachments (not yet handled by applesauce)

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

@@ -20,6 +20,7 @@ import { isNip05, resolveNip05 } from "@/lib/nip05";
 import { getDisplayName, getQuotePointer } from "@/lib/nostr-utils";
 import { isValidHexPubkey } from "@/lib/nostr-validation";
 import { getProfileContent } from "applesauce-core/helpers";
+import { getSeenRelays } from "applesauce-core/helpers/relays";
 import { EventFactory } from "applesauce-core/event-factory";
 import { ReactionBlueprint } from "applesauce-common/blueprints";
 
@@ -232,8 +233,22 @@ export class NipC7Adapter extends ChatProtocolAdapter {
     factory.setSigner(activeSigner);
 
     const tags: string[][] = [["p", partner.pubkey]];
+
+    // Add q-tag for replies (per NIP-C7 quote tag format)
+    // Format: ["q", eventId, relayUrl, pubkey]
     if (options?.replyTo) {
-      tags.push(["q", options.replyTo]); // NIP-C7 quote tag for threading
+      const replyEvent = eventStore.getEvent(options.replyTo);
+      if (replyEvent) {
+        // Get a relay hint from where we've seen this event
+        const seenRelays = getSeenRelays(replyEvent);
+        const relayHint =
+          seenRelays && seenRelays.size > 0 ? [...seenRelays][0] : "";
+        // Full q-tag with relay hint and author pubkey
+        tags.push(["q", options.replyTo, relayHint, replyEvent.pubkey]);
+      } else {
+        // Fallback: just the event ID
+        tags.push(["q", options.replyTo]);
+      }
     }
 
     // Add NIP-30 emoji tags