fix(app): 僅輸出 Codex 最後回覆

app/main.js

@@ -183,11 +183,13 @@ function readExecutionConfig() {
   };
 }
 
-function codexExecArgs(model, prompt) {
+function codexExecArgs(model, prompt, lastMessageFile) {
   return [
     "exec",
     "--dangerously-bypass-approvals-and-sandbox",
     "--skip-git-repo-check",
+    "--output-last-message",
+    lastMessageFile,
     "--model",
     model,
     prompt,
@@ -197,7 +199,10 @@ function codexExecArgs(model, prompt) {
 function runCodex(model, prompt) {
   return new Promise((resolve) => {
     const { timeoutMs, outputLimitBytes, workspace } = readExecutionConfig();
-    const args = codexExecArgs(model, prompt);
+    const tempDir = makeTempDir(process.env.CODEX_HOME || "/root/.codex");
+    const lastMessageFile = path.join(tempDir, "last-message.txt");
+    tempFiles.trackFile(lastMessageFile);
+    const args = codexExecArgs(model, prompt, lastMessageFile);
 
     // This Docker Action runs inside an ephemeral CI container where Codex must be
     // able to edit the checked-out workspace without interactive approvals.
@@ -210,7 +215,6 @@ function runCodex(model, prompt) {
       output.append(Buffer.from(`Codex execution timed out after ${timeoutMs} ms.\n`));
     }, timeoutMs);
 
-    child.stdout.pipe(process.stdout);
     child.stderr.pipe(process.stdout);
 
     child.stdout.on("data", (chunk) => {
@@ -235,7 +239,14 @@ function runCodex(model, prompt) {
         output.append(Buffer.from(`Codex process terminated by signal ${signal}.\n`));
       }
 
-      resolve({ status: code ?? 1, output: output.toString() });
+      let lastMessage = "";
+      try {
+        lastMessage = fs.readFileSync(lastMessageFile, "utf8");
+      } catch {
+        lastMessage = "";
+      }
+
+      resolve({ status: code ?? 1, output: lastMessage || output.toString() });
     });
   });
 }
@@ -312,6 +323,9 @@ function setupAuth(oauth, codexHome) {
 async function runCodexAction({ oauth, model, codexHome, prompt }) {
   const lockHandle = setupAuth(oauth, codexHome);
   const result = await runCodex(model, prompt);
+  if (result.output) {
+    process.stdout.write(result.output.endsWith("\n") ? result.output : `${result.output}\n`);
+  }
   appendGithubOutput(result.status === 0 ? "completed" : "failed", result.output);
 
   if (lockHandle !== undefined) {