Review: PR #2122 — fix: limit control prompt request body

✅ LGTM — 简洁有效的安全加固。

审查要点

1. Body limit 设置 — 32MB 对 control prompt 合理（远大于 callback 的 256KB，但仍有上限防护）。
2. 错误处理 — 返回 413 Payload Too Large，语义准确。
3. 代码组织 — 常量和检查位置合理，与现有 callback body limit 保持一致的模式。

✅ 可以合并。

Review: PR #2122 — fix: limit control prompt request body

✅ LGTM — 简洁有效的安全加固。32MB body limit 合理，错误处理返回 413 语义准确。

Review: PR #2122 — fix: limit control prompt request body

✅ LGTM — Clean, focused security hardening that follows the established CALLBACK_BODY_LIMIT_BYTES pattern.

Assessment

• Correctness — DefaultBodyLimit::max() at the route level rejects oversized bodies before the Json extractor. Correct placement, matches the callback route pattern.
• Limit choice — 32 MB is reasonable for prompts with attachments, and explicitly documented as a constant.
• Test — Regression test correctly validates the 413 response path.

Follow-up suggestion

⚠️ /control/agents/{agent_id}/debug-prompt (line 468) accepts POST bodies without an explicit DefaultBodyLimit — the same gap this PR closes for control_prompt. Not a blocker, but worth addressing in a follow-up to close the surface on all body-accepting control routes.

💡 The test allocates ~33 MB in a single String. Acceptable; if CI memory is a concern, 32 * 1024 * 1024 + 1 bytes would suffice.