fix(channels/buzz): accept subscription without EOSE after auth

The Buzz relay authenticates via NIP-42 but does not send EndOfStoredEvents
after the second subscription. Waiting for EOSE caused a 15s timeout and
channel startup failure.

After auth, wait a short grace period (3s) for either EOSE or a rejection.
If neither arrives, the subscription was accepted — the relay simply doesn
not send EOSE, which is valid per NIP-01 (EOSE is optional for live-only
subscriptions).

pkg/channels/buzz/buzz.go

@@ -195,6 +195,12 @@ func (c *BuzzChannel) subscribeAuthed(
 			"pubkey": c.publicKey,
 		})
 
+		// postAuthGrace is how long we wait after re-subscribing for either
+		// EOSE (relay sends end-of-stored-events) or a rejection. If neither
+		// arrives, the relay accepted the subscription but doesn't send EOSE —
+		// which is fine, we just start consuming events.
+		const postAuthGrace = 3 * time.Second
+
 		authed, err := c.relay.Subscribe(ctx, filters)
 		if err != nil {
 			return nil, fmt.Errorf("buzz subscribe after auth failed: %w", err)
@@ -208,8 +214,14 @@ func (c *BuzzChannel) subscribeAuthed(
 			// A second rejection means the identity is not permitted, not that
 			// the handshake was mistimed — retrying would loop forever.
 			return nil, fmt.Errorf("buzz relay rejected subscription after auth: %s", reason)
-		case <-time.After(subscribeTimeout):
-			return nil, fmt.Errorf("buzz timed out waiting for subscription after auth")
+		case <-time.After(postAuthGrace):
+			// No EOSE and no rejection within the grace period — the relay
+			// accepted the subscription. Some relays (including Buzz) don't
+			// send EOSE after auth, so this is the expected success path.
+			logger.InfoCF("buzz", "Subscription accepted after auth (no EOSE)", map[string]any{
+				"relay": c.config.RelayURL,
+			})
+			return authed, nil
 		}
 
 	case <-time.After(subscribeTimeout):