- Remove docs/design/ directory (notification-service-refactoring,
pluggable-llm-providers, ui-theme-language) — these are internal
architecture/refactoring documents that should not be in public
documentation navigation per project convention
- Extract UI theme conventions from ui-theme-language.md into
CONTRIBUTING.md as contributor guidelines
- Remove Architecture & design section from docs/README.md and
docs/README.zh-CN.md index pages
- Update README.md link from Architecture docs to Documentation index