docs(readme): consolidate triple frontend architecture sections}
- Merge detailed "Modern Triple Frontend Architecture" section into the existing "Triple GUI" overview to eliminate redundancy - Condense per-frontend bullet points into single lines with key tech highlights (build tools, state management, virtual scrolling) - Consolidate shared infrastructure details (Socket.IO, translations, themes, Web Workers, Playwright) into one bullet point - Add "full feature parity" clarification to the introductory sentence - Net reduction of 26 lines by removing duplicated content