feat(chat): add private message unlock flow

src/stores/chat/chat-machine.actors.ts

@@ -105,6 +105,41 @@ export const loadMoreHistoryActor = fromPromise<
   };
 });
 
+export const unlockPrivateMessageActor = fromPromise<
+  {
+    messageId: string;
+    response: import("@/data/dto/chat").UnlockPrivateResponse;
+  },
+  { messageId: string }
+>(async ({ input }) => {
+  const result = await chatRepo.unlockPrivateMessage(input.messageId);
+  if (Result.isErr(result)) {
+    log.error("[chat-machine] unlockPrivateMessageActor failed", {
+      messageId: input.messageId,
+      error: result.error,
+    });
+    throw result.error;
+  }
+
+  if (result.data.unlocked && result.data.content != null) {
+    const localResult = await chatRepo.markPrivateMessageUnlockedInLocal(
+      input.messageId,
+      result.data.content,
+    );
+    if (Result.isErr(localResult)) {
+      log.error("[chat-machine] unlockPrivateMessageActor local sync failed", {
+        messageId: input.messageId,
+        error: localResult.error,
+      });
+    }
+  }
+
+  return {
+    messageId: input.messageId,
+    response: result.data,
+  };
+});
+
 // ============================================================
 // WebSocket: long-lived callback
 // ============================================================