feat: auto-background timed-out foreground bash commands

[liruifengv]

Related Issue

N/A — no linked issue; the problems are explained below.

Problem

Two related issues around background tasks:

1. A foreground Bash command that hits its timeout (default 60s, max 300s) is killed outright, losing all progress on long-running commands.
2. The agent frequently calls TaskOutput with block=true to wait for background task results, which re-blocks the main thread and defeats the purpose of background execution.

What changed

• Timed-out foreground Bash commands now move to the background instead of being killed. On timeout the task is detached (reusing the ctrl+b detach path) and re-armed with the 600s default background deadline; a second timeout still kills it. The tool call returns immediately and completion arrives as the usual background-task notification. Controlled by a new config option [background] bash_auto_background_on_timeout (default true; set to false to restore kill-on-timeout). Agents without background tooling keep the kill behavior, since a detached task would be unobservable there.
• TaskOutput prompts tightened to keep background tasks non-blocking. The tool description is repositioned as a snapshot reader (dropping "explicitly wait for completion" as a primary use), the block parameter description carries the discouragement, the Bash tool description steers away from blocking on just-launched tasks, and a blocking wait that times out now appends an in-result next_step nudge telling the agent not to block again.
• Config reference updated in docs/en and docs/zh; changesets included (minor for the timeout behavior, patch for the prompt tuning).

Checklist

• I have read the CONTRIBUTING document.
• I have linked a related issue, or explained the problem above.
• I have added tests that prove my feature works.
• Ran gen-changesets skill, or this PR needs no changeset.
• Ran gen-docs skill, or this PR needs no doc update.

[changeset-bot]

🦋 Changeset detected

Latest commit: f2cd847

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@moonshot-ai/kimi-code	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[pkg-pr-new]

pnpm dlx https://pkg.pr.new/@moonshot-ai/kimi-code@f2cd847

npx https://pkg.pr.new/@moonshot-ai/kimi-code@f2cd847

commit: f2cd847

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: 5ea94be2b5

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".

[liruifengv]

@codex review

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: f2cd8472ed

ℹ️ About Codex in GitHub

Codex has been enabled to automatically review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

When you sign up for Codex through ChatGPT, Codex can also answer questions or update the PR, like "@codex address that feedback".