feat(ui): components, routes and styles

Sidebar (lazy tree, keyboard navigation, saved searches), page view with
typed properties, tasks, tags, calendar and clip dialogs, settings with
shortcut rebinding, canvas, database and board views.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/routes/+layout.svelte

@@ -0,0 +1,11 @@
+<script>
+  import '@fontsource-variable/inter';
+  import '@fontsource/jetbrains-mono/400.css';
+  import '@fontsource/jetbrains-mono/500.css';
+  import 'katex/dist/katex.min.css';
+  import '../app.css';
+
+  let { children } = $props();
+</script>
+
+{@render children()}