refactor(codex): 將 app-server 取帳號邏輯抽到 app/codex_account.py

把原本內嵌在 action.yml heredoc 的 python 抽成獨立檔 app/codex_account.py，
action 改以 $GITHUB_ACTION_PATH/app/codex_account.py 呼叫，便於閱讀與維護。

action.yml

@@ -52,42 +52,6 @@ runs:
   - name: 取得登入帳號
     id: account
     run: |
-      cat > "$RUNNER_TEMP/codex_account.py" <<'PY'
-      import json, subprocess, time
-
-      p = subprocess.Popen(
-          ["codex", "app-server"],
-          stdin=subprocess.PIPE, stdout=subprocess.PIPE,
-          stderr=subprocess.DEVNULL, text=True, bufsize=1,
-      )
-
-      def send(obj):
-          p.stdin.write(json.dumps(obj) + "\n")
-          p.stdin.flush()
-
-      send({"jsonrpc": "2.0", "id": 1, "method": "initialize",
-            "params": {"clientInfo": {"name": "ci", "version": "1.0"}}})
-      send({"jsonrpc": "2.0", "method": "initialized", "params": {}})
-      send({"jsonrpc": "2.0", "id": 2, "method": "account/read", "params": {}})
-
-      email = ""
-      deadline = time.time() + 25
-      while time.time() < deadline:
-          line = p.stdout.readline()
-          if not line:
-              break
-          try:
-              msg = json.loads(line)
-          except Exception:
-              continue
-          if msg.get("id") == 2:
-              account = (msg.get("result") or {}).get("account") or {}
-              email = account.get("email") or ""
-              break
-
-      p.terminate()
-      print(email)
-      PY
-      email="$(python3 "$RUNNER_TEMP/codex_account.py")"
+      email="$(python3 "$GITHUB_ACTION_PATH/app/codex_account.py")"
       printf 'email=%s\n' "$email" >> "$GITHUB_OUTPUT"
     shell: bash