feature: move all shadcn related code to src/shared/shadcn

src/shared/shadcn/ui/sidebar/sidebar-menu-action.svelte

@@ -0,0 +1,43 @@
+<script lang="ts">
+    import { cn, type WithElementRef } from '$shared/shadcn/utils/shadcn-utils.js';
+import type { Snippet } from 'svelte';
+import type { HTMLButtonAttributes } from 'svelte/elements';
+
+let {
+    ref = $bindable(null),
+    class: className,
+    showOnHover = false,
+    children,
+    child,
+    ...restProps
+}: WithElementRef<HTMLButtonAttributes> & {
+    child?: Snippet<[{ props: Record<string, unknown> }]>;
+    showOnHover?: boolean;
+} = $props();
+
+const mergedProps = $derived({
+    class: cn(
+        'text-sidebar-foreground ring-sidebar-ring hover:bg-sidebar-accent hover:text-sidebar-accent-foreground peer-hover/menu-button:text-sidebar-accent-foreground absolute end-1 top-1.5 flex aspect-square w-5 items-center justify-center rounded-md p-0 outline-hidden transition-transform focus-visible:ring-2 [&>svg]:size-4 [&>svg]:shrink-0',
+        // Increases the hit area of the button on mobile.
+        'after:absolute after:-inset-2 md:after:hidden',
+        'peer-data-[size=sm]/menu-button:top-1',
+        'peer-data-[size=default]/menu-button:top-1.5',
+        'peer-data-[size=lg]/menu-button:top-2.5',
+        'group-data-[collapsible=icon]:hidden',
+        showOnHover
+            && 'peer-data-[active=true]/menu-button:text-sidebar-accent-foreground group-focus-within/menu-item:opacity-100 group-hover/menu-item:opacity-100 data-[state=open]:opacity-100 md:opacity-0',
+        className,
+    ),
+    'data-slot': 'sidebar-menu-action',
+    'data-sidebar': 'menu-action',
+    ...restProps,
+});
+</script>
+
+{#if child}
+    {@render child({ props: mergedProps })}
+{:else}
+    <button bind:this={ref} {...mergedProps}>
+        {@render children?.()}
+    </button>
+{/if}