fix: filebrowser auth cookie path for video/audio playback

Cookie was scoped to /app/filebrowser but Cloud page reads it from
/dashboard/cloud — cookie was invisible. Changed to path=/ so the
auth token is accessible from any page for fetchBlobUrl calls.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

neode-ui/src/api/filebrowser-client.ts

@@ -74,7 +74,7 @@ class FileBrowserClient {
 
       const expires = new Date(Date.now() + 24 * 60 * 60 * 1000).toUTCString()
       const secure = window.location.protocol === 'https:' ? '; Secure' : ''
-      document.cookie = `auth=${token}; path=/app/filebrowser; SameSite=Lax${secure}; expires=${expires}`
+      document.cookie = `auth=${token}; path=/; SameSite=Lax${secure}; expires=${expires}`
       this._authenticated = true
       return true
     } catch {