style: refine admin & me UI — card forms, back arrows, avatar in admin sidebar, Empty component

- Replace ← text with icon-[ri--arrow-left-line] in admin and me layouts
- Add avatar + admin shield badge to admin sidebar header
- Wrap all admin edit forms in Card (bg-card/50 border-primary/20) with styled inputs
- Fix sm:pl-6 → lg:pl-6 so extra left padding only applies when sidebar is visible
- Update security form submit button to gradient style matching profile
- Remove "View Public Profile" button from me/profile
- Use shadcn-svelte Empty component for recordings empty state
- Install empty component via shadcn-svelte

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/frontend/src/lib/components/ui/empty/empty-content.svelte

@@ -0,0 +1,23 @@
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		...restProps
+	}: WithElementRef<HTMLAttributes<HTMLDivElement>> = $props();
+</script>
+
+<div
+	bind:this={ref}
+	data-slot="empty-content"
+	class={cn(
+		"flex w-full max-w-sm min-w-0 flex-col items-center gap-4 text-sm text-balance",
+		className
+	)}
+	{...restProps}
+>
+	{@render children?.()}
+</div>

packages/frontend/src/lib/components/ui/empty/empty-description.svelte

@@ -0,0 +1,23 @@
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		...restProps
+	}: WithElementRef<HTMLAttributes<HTMLDivElement>> = $props();
+</script>
+
+<div
+	bind:this={ref}
+	data-slot="empty-description"
+	class={cn(
+		"text-muted-foreground [&>a:hover]:text-primary text-sm/relaxed [&>a]:underline [&>a]:underline-offset-4",
+		className
+	)}
+	{...restProps}
+>
+	{@render children?.()}
+</div>

packages/frontend/src/lib/components/ui/empty/empty-header.svelte

@@ -0,0 +1,20 @@
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		...restProps
+	}: WithElementRef<HTMLAttributes<HTMLDivElement>> = $props();
+</script>
+
+<div
+	bind:this={ref}
+	data-slot="empty-header"
+	class={cn("flex max-w-sm flex-col items-center gap-2 text-center", className)}
+	{...restProps}
+>
+	{@render children?.()}
+</div>

packages/frontend/src/lib/components/ui/empty/empty-media.svelte

@@ -0,0 +1,41 @@
+<script lang="ts" module>
+	import { tv, type VariantProps } from "tailwind-variants";
+
+	export const emptyMediaVariants = tv({
+		base: "mb-2 flex shrink-0 items-center justify-center [&_svg]:pointer-events-none [&_svg]:shrink-0",
+		variants: {
+			variant: {
+				default: "bg-transparent",
+				icon: "bg-muted text-foreground flex size-10 shrink-0 items-center justify-center rounded-lg [&_svg:not([class*='size-'])]:size-6",
+			},
+		},
+		defaultVariants: {
+			variant: "default",
+		},
+	});
+
+	export type EmptyMediaVariant = VariantProps<typeof emptyMediaVariants>["variant"];
+</script>
+
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		variant = "default",
+		...restProps
+	}: WithElementRef<HTMLAttributes<HTMLDivElement>> & { variant?: EmptyMediaVariant } = $props();
+</script>
+
+<div
+	bind:this={ref}
+	data-slot="empty-icon"
+	data-variant={variant}
+	class={cn(emptyMediaVariants({ variant }), className)}
+	{...restProps}
+>
+	{@render children?.()}
+</div>

packages/frontend/src/lib/components/ui/empty/empty-title.svelte

@@ -0,0 +1,20 @@
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		...restProps
+	}: WithElementRef<HTMLAttributes<HTMLDivElement>> = $props();
+</script>
+
+<div
+	bind:this={ref}
+	data-slot="empty-title"
+	class={cn("text-lg font-medium tracking-tight", className)}
+	{...restProps}
+>
+	{@render children?.()}
+</div>

packages/frontend/src/lib/components/ui/empty/empty.svelte

@@ -0,0 +1,23 @@
+<script lang="ts">
+	import { cn, type WithElementRef } from "$lib/utils.js";
+	import type { HTMLAttributes } from "svelte/elements";
+
+	let {
+		ref = $bindable(null),
+		class: className,
+		children,
+		...restProps
+	}: WithElementRef<HTMLAttributes<HTMLDivElement>> = $props();
+</script>
+
+<div
+	bind:this={ref}
+	data-slot="empty"
+	class={cn(
+		"flex min-w-0 flex-1 flex-col items-center justify-center gap-6 rounded-lg border-dashed p-6 text-center text-balance md:p-12",
+		className
+	)}
+	{...restProps}
+>
+	{@render children?.()}
+</div>

packages/frontend/src/lib/components/ui/empty/index.ts

@@ -0,0 +1,22 @@
+import Root from "./empty.svelte";
+import Header from "./empty-header.svelte";
+import Media from "./empty-media.svelte";
+import Title from "./empty-title.svelte";
+import Description from "./empty-description.svelte";
+import Content from "./empty-content.svelte";
+
+export {
+	Root,
+	Header,
+	Media,
+	Title,
+	Description,
+	Content,
+	//
+	Root as Empty,
+	Header as EmptyHeader,
+	Media as EmptyMedia,
+	Title as EmptyTitle,
+	Description as EmptyDescription,
+	Content as EmptyContent,
+};