feat(ui): project details panel + compact/responsive cards; rename Sentinel→Yerin (red); migrate research_notes

- Project card expands to show description + status + dates (was only the research stub)
- Cards compacted + responsive (actions wrap on narrow)
- Sentinel renamed Yerin everywhere (#/yerin, red 'Sage of the Endless Sword' theme + red sidebar dot)
- void1 importer now carries research_notes/last_researched_at (was dropped)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/app.js

@@ -22,7 +22,7 @@ const VIEWS = {
   search:          () => import('./views/search.js'),
   inbox:           () => import('./views/inbox.js'),
   'sacred-valley': () => import('./views/sacred_valley.js'),
-  sentinel:        () => import('./views/sentinel.js'),
+  yerin:           () => import('./views/sentinel.js'),
   'little-blue':   () => import('./views/little_blue.js'),
   terminal:        () => import('./views/terminal.js'),
   settings:        () => import('./views/settings.js'),