Complete instant diplomacy response parity

app/game-api/src/messages/store.ts

@@ -140,6 +140,25 @@ export const fetchMessageById = async (db: DatabaseClient, id: number): Promise<
     };
 };
 
+export const fetchMessageByIdForUpdate = async (db: DatabaseClient, id: number): Promise<StoredMessage | null> => {
+    const rows = await db.$queryRaw<MessageRow[]>`
+        SELECT id, mailbox, type, src, dest, time, valid_until, message
+        FROM message
+        WHERE id = ${id} AND valid_until > NOW()
+        LIMIT 1
+        FOR UPDATE
+    `;
+    const row = rows[0];
+    if (!row) return null;
+    return {
+        id: row.id,
+        mailbox: row.mailbox,
+        msgType: row.type,
+        time: new Date(row.time),
+        payload: parsePayload(row.message),
+    };
+};
+
 export const invalidateMessages = async (db: DatabaseClient, ids: number[]): Promise<void> => {
     const uniqueIds = Array.from(new Set(ids.filter((id) => Number.isInteger(id) && id > 0)));
     if (uniqueIds.length === 0) return;