docs: clarify features and polish bilingual README

[linnnn89]

Summary

The README buried background UI inspection, text-only LLM support and UI-to-source workflows beneath setup details and historical validation records. Reorganize both languages around features, a practical disabled-button investigation, recommended workspace configuration and common workflows, with detailed engineering records linked from existing documentation.

Polish Chinese terminology and sentence structure, align the English text, and retain the maintainer's everyday experience of faster, more accurate inspection than screenshot-based Computer Use. Keep the recorded response-size example and the existing UIA, source-mapping and desktop-session requirements. Append the work-log entry required by CONTRIBUTING.

Validation

• Verified 10 local links, 6 JSON examples, 7 npm scripts and 16 registered tool names.
• Validated 4 tool-call examples against the current source schemas; bilingual configurations and tool tables agree.
• git diff --check passed.
• Documentation only; no production code, dependencies or managed Skill changes. Runtime tests were not rerun locally.
• Required Node 22/24 and CodeQL checks must pass on this PR's current head before merging.