- Rename "LLMs" section to "Engines" with brain icon
- Add three sub-pages (Language Models / Speech to Text / Text to Speech) following the same nav-tree pattern as Settings and My Voices
- Rewrite s-llms.html: three s-engines-page divs, docker container grids (dc-grid-tts, dc-grid-stt), VibeVoice card in TTS section, static cloud API cards per category
- Add navEnginesCat() and applyEnginesPage() to nav.js; engines tree open/close in showSection()
- Remove obsolete initLlmCatTabs IIFE; fix dc-refresh-btn from ID to class-based querySelectorAll
- Make integration cards in Connect Apps collapsible (collapsed by default) with favicon/icon prepended to h3
- Unify all Engines card grids to minmax(380px, 1fr) so local, docker, and cloud cards are the same width
- Add s-engines-page CSS (display:none / is-active:flex)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>