docs(WebUI Smoke CLI): operator README in English and Korean

## Parent

- Epic: [FR-2871](https://lablup.atlassian.net/browse/FR-2871)
- Spec Task: [FR-2872](https://lablup.atlassian.net/browse/FR-2872)
- Spec: `.specs/FR-2871-webui-smoke-cli/spec.md` § FR-I

## Goal

Write a one-page operator README in English and Korean covering extract → chmod → run → read report → known issues, plus a troubleshooting section. This is gated on FR-H because the CLI surface and packaging must be final before we document them.

## Acceptance criteria

- [ ] One-page README in **English and Korean** covering: extract → chmod → run → read report → known issues.
- [ ] Troubleshooting section covers: self-signed cert, macOS quarantine workaround, Windows SmartScreen workaround, "login failed" vs "endpoint unreachable" disambiguation, leftover resource cleanup (`bai-smoke cleanup --prefix bai-smoke-`).
- [ ] README fits on one printed page in either language.

## In scope

- `packages/backend.ai-webui-smoke-cli/README.md` (EN)
- `packages/backend.ai-webui-smoke-cli/README.ko.md` (KO)

## Out of scope

- WebUI user-manual integration (separate effort if requested)
- Public marketing copy

## Test plan

- Print preview each README at A4 with default browser margins; confirm one page.
- Have one non-author Field-Ops engineer run through the README on a fresh host.

JIRA Issue: FR-2883

[FR-2871]: https://lablup.atlassian.net/browse/FR-2871?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ
[FR-2872]: https://lablup.atlassian.net/browse/FR-2872?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ