Adds a /gridstack route demonstrating GridStackLayout: four default
widgets (line/bar/pie chart cards plus a usage hint), buttons to add and
remove widgets at runtime, a reset-layout button and a layout-change
status line. Layout is persisted per browser via the existing
localStorage support. The view gets its own SideNavItem in MainLayout
and full de/en/es translations.
Fixes an infinite recursion in GridStackLayout.add(Component): a
single-argument add(item) resolves to that overload rather than the
varargs one, so its delegation to add(item) called itself. It now
appends through the element API and passes a GridStackItem through
unwrapped.
Adds the first test sources (browserless UI tests) covering the view's
widget count and the add/remove buttons.
Closes#7
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PYAcKoXKPN3rJ7nBroKZkc
Pit Friedrich