fix(cli): clarify prompt mode login guidance

[Fengzdadi]

Related Issue

No related issue. This came from trying kimi -p hello in a fresh configuration and seeing a prompt-mode error that only mentioned editing config.toml.

Problem

When prompt mode runs without a configured model, the current error tells users to set default_model in config.toml. That is technically correct, but it misses the normal first-run path for Kimi Code users: start the interactive CLI and run /login to provision a model before retrying prompt mode.

What changed

Updated the prompt-mode missing-model error to point users to kimi + /login first, while still mentioning default_model for manual configuration. The existing prompt-mode test now asserts the friendlier guidance, and a patch changeset records the CLI-visible wording change.

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.

Validation:

• pnpm --filter @moonshot-ai/kimi-code exec vitest run test/cli/run-prompt.test.ts
• pnpm -C apps/kimi-code run build
• KIMI_CODE_HOME=/private/tmp/kimi-code-prompt-message-check node apps/kimi-code/dist/main.mjs -p hello

[changeset-bot]

🦋 Changeset detected

Latest commit: 27c9eb7

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	Patch

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[liruifengv]

LGTM! Thank you!