fix(session-recovery): detect empty messages with zero parts

Previously, findEmptyContentMessageFromStorage only detected messages
with parts.length > 0 that had no content. This missed the case where
a message has zero parts entirely, causing infinite recovery loops.

Author: code-yeongyu

src/hooks/session-recovery.ts

@@ -349,7 +349,7 @@ function findEmptyContentMessageFromStorage(sessionID: string): string | null {
       return false
     })
 
-    if (!hasContent && parts.length > 0) {
+    if (!hasContent) {
       return msg.id
     }
   }