feat(desktop): manage remote runtime host credentials

[M4n5ter]

English

Summary

Add credential maintenance to the per-computer management surface for SSH-managed Runtime Hosts. Desktop can inspect non-secret credential metadata, identify its own credential, rotate it through the existing verified pairing path, and explicitly revoke an obsolete credential.

Credential authority remains in Runtime Host. Desktop invokes Host-local operator commands over SSH, secrets never enter renderer state or terminal output, and privileged access-management mutations remain restricted to the Host-local operator; ordinary remote Client grants and remotely available operations are unchanged.

Fixes #3418

Verification

• npm run typecheck
• npm run lint
• npm run format:check
• npm run astryx:surface-inventory
• affected Desktop and CLI tests
• isolated CLI release package build
• Desktop end-to-end list, revoke, and rotate against a managed Linux Runtime Host

AI use

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Codex implemented and verified the change under maintainer direction and review

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — described under Summary above
• No

简体中文

概要

为 SSH 托管的 Runtime Host 增加 per-computer credential 维护界面。Desktop 可以查看不含 secret 的 credential metadata、识别自身 credential、通过现有已验证 pairing 路径安全轮换，并明确撤销废弃 credential。

Credential authority 仍属于 Runtime Host。Desktop 只通过 SSH 调用 Host-local operator command；secret 不进入 renderer state 或 terminal output，privileged access-management mutation 仍仅限 Host-local operator；普通 remote Client grants 与远程可用 operations 保持不变。

Fixes #3418

验证

• npm run typecheck
• npm run lint
• npm run format:check
• npm run astryx:surface-inventory
• 受影响的 Desktop 与 CLI tests
• 隔离环境中的 CLI release package 构建
• 在 managed Linux Runtime Host 上通过 Desktop 完成 list、revoke 与 rotate 端到端验证

AI 使用

• 没有生成式工具作出实质贡献
• 生成式工具作出了实质贡献

工具与范围：Codex 在维护者指导与审核下实现并验证了本次变更

Checklist

• 测试覆盖本次变更，且缺少变更时会失败
• lint、format、typecheck 与受影响 suites 已在本地通过

本 PR 是否改变行为？

• 是——已在概要中说明
• 否