docs: simplify README and automate Korean localization

[Kinirin]

Summary

• simplify README.md into a version-independent project overview
• use pip install ptsip for latest published installation and document minimum-compatible dependency constraints
• keep English/Korean navigation in both READMEs
• make README.md the canonical source and mark README.ko.md as generated
• add GitHub Models based translation automation using the repository GITHUB_TOKEN
• add reusable structural validation for headings, fenced code blocks, links, normative keywords, and suspicious output length

Automation design

• triggers only when README.md changes on main, plus manual workflow dispatch
• uses models: read and contents: write; no separate model API secret
• commits only README.ko.md when translation actually changes
• bot pushes use GITHUB_TOKEN, avoiding recursive push-triggered workflow runs

Validation

• branch is based on current main SHA 6db3a37c0ee6ba8c55b2facfff699a3cafea2573
• translation helper compiles successfully with Python
• workflow YAML parses successfully
• compare against main contains only README localization/automation files