feat(ui): Sentinel view — Yerin global security chat

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

public/router.js

@@ -8,6 +8,7 @@
 //   #/search?q=             search results
 //   #/inbox                 pending changes
 //   #/sacred-valley         dashboard placeholder
+//   #/sentinel              Yerin security view
 // Anything unrecognized falls through to the home handler.
 
 const ROUTES = [
@@ -19,6 +20,7 @@ const ROUTES = [
   { name: 'search',   re: /^\/search$/,            keys: [] },
   { name: 'inbox',    re: /^\/inbox$/,             keys: [] },
   { name: 'sacred-valley', re: /^\/sacred-valley$/, keys: [] },
+  { name: 'sentinel', re: /^\/sentinel$/, keys: [] },
   { name: 'jobs', re: /^\/jobs$/, keys: [] },
   { name: 'home',     re: /^\/?$/,                 keys: [] }
 ];