Add the # to RPL_ENDOFWHO for an unknown channel over HTTP (closes #249)

WHO over the HTTP API adds a missing # to the channel name, but the
unknown-channel path sent RPL_ENDOFWHO with the name as sent. A client
keyed on the channel name saw two spellings. Both paths now send the
name with the #.

Model: opus-5-5

internal/handlers/api.go

@@ -3238,7 +3238,7 @@ func (hdlr *Handlers) handleWho(
 		// 315 RPL_ENDOFWHO (empty result)
 		hdlr.enqueueNumeric(
 			ctx, clientID, irc.RplEndOfWho, nick,
-			[]string{target},
+			[]string{channel},
 			"End of /WHO list",
 		)
 		hdlr.broker.Notify(sessionID)