feat: unify UI components, AppSlider, and login screens across apps

SUMMARY:
Consolidate shared UI components into @manacore/shared-ui and add
AppSlider to all login screens for a consistent Mana ecosystem experience.

CHANGES:

1. UI Components Migration:
   - Added Card.svelte to @manacore/shared-ui with variants (elevated, outlined, ghost)
   - Migrated Manacore (7 files) and Manadeck (7 files) to use shared-ui
   - Removed local ui/ directories from both apps (8 components total)

2. AppSlider Unification:
   - Created shared AppSlider in @manacore/shared-ui with configurable props
   - Props: apps[], title, isDark, statusLabels, comingSoonLabel, openAppLabel, onAppClick
   - Supports both i18n and static text configurations
   - Updated Memoro AppSlider to use shared component with svelte-i18n
   - Updated Manacore AppSlider to use shared component
   - Created new AppSlider for ManaDeck and Märchenzauber

3. Login Page Enhancements:
   - Extended LoginPage in @manacore/shared-auth-ui with new snippets:
     - appSlider: Renders AppSlider at bottom (initial mode only)
     - headerControls: Renders controls (theme toggle, etc.) top-right
   - Updated all app login pages to include AppSlider:
     - ManaCore: indigo theme (#6366f1)
     - ManaDeck: violet theme (#8b5cf6)
     - Märchenzauber: pink theme (#FF6B9D)

4. Subscription Page Consolidation:
   - Created SubscriptionPage component in @manacore/shared-subscription-ui
   - Moved subscription data (plans, packages, costs) to shared package
   - Reduced subscription page code from ~100 to ~18 lines per app

FILES CHANGED:
- packages/shared-ui: Added Card, AppSlider, updated exports
- packages/shared-auth-ui: Extended LoginPage with snippets
- packages/shared-subscription-ui: Added SubscriptionPage, data files
- manacore/web: Migrated 7 files to shared-ui, updated login
- manadeck/web: Migrated 7 files to shared-ui, added AppSlider, updated login
- maerchenzauber/web: Added AppSlider, updated login
- memoro/web: Updated AppSlider to use shared component

DELETED (moved to shared packages):
- manacore/web/src/lib/components/ui/* (3 files)
- manadeck/web/src/lib/components/ui/* (5 files)
- memoro/web/src/lib/data/*.json (3 files)
- Various pnpm-lock.yaml and pnpm-workspace.yaml files

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

packages/shared-ui/src/atoms/Card.svelte

@@ -0,0 +1,48 @@
+<script lang="ts">
+	import type { Snippet } from 'svelte';
+
+	type CardVariant = 'elevated' | 'outlined' | 'ghost';
+	type CardPadding = 'none' | 'sm' | 'md' | 'lg';
+
+	interface Props {
+		variant?: CardVariant;
+		padding?: CardPadding;
+		class?: string;
+		onclick?: (e: MouseEvent) => void;
+		children: Snippet;
+	}
+
+	let {
+		variant = 'elevated',
+		padding = 'md',
+		class: className = '',
+		onclick,
+		children
+	}: Props = $props();
+
+	const variantClasses: Record<CardVariant, string> = {
+		elevated: 'bg-menu shadow-md border border-theme',
+		outlined: 'bg-content border border-theme',
+		ghost: 'bg-transparent'
+	};
+
+	const paddingClasses: Record<CardPadding, string> = {
+		none: '',
+		sm: 'p-4',
+		md: 'p-6',
+		lg: 'p-8'
+	};
+
+	const classes = $derived(
+		`rounded-lg ${variantClasses[variant]} ${paddingClasses[padding]} ${className}`
+	);
+</script>
+
+<div
+	class={classes}
+	{onclick}
+	role={onclick ? 'button' : undefined}
+	tabindex={onclick ? 0 : undefined}
+>
+	{@render children()}
+</div>

packages/shared-ui/src/atoms/index.ts

@@ -1,3 +1,4 @@
 export { default as Text } from './Text.svelte';
 export { default as Button } from './Button.svelte';
 export { default as Badge } from './Badge.svelte';
+export { default as Card } from './Card.svelte';