feat(client): add component library and simplify routing (#66)

* feat(client): add component library and simplify routing

Remove tab layout, explore page, modal, and unused template
components. Replace with single-page layout and a dev component
showcase with per-component detail pages.

- Add Button with label prop, leading/trailing icon support
- Add FeedCard, SerifText, SansSerifText, MonospaceText
- Add colocated *.showcase.tsx files for each component
- Use Stack navigator with themed headers

Co-authored-by: Ona <no-reply@ona.com>

* fix(client): render showcase as JSX component

Co-authored-by: Ona <no-reply@ona.com>

* chore(client): remove dead code chain

Remove ThemedText, useThemeColor, useColorScheme hook,
Colors, and Fonts — none referenced by current screens.

Co-authored-by: Ona <no-reply@ona.com>

---------

Co-authored-by: Ona <no-reply@ona.com>

apps/aelis-client/src/app/components/[name].tsx

@@ -0,0 +1,48 @@
+import { useLocalSearchParams, useNavigation } from "expo-router"
+import { useEffect } from "react"
+import { ScrollView, View } from "react-native"
+import tw from "twrnc"
+
+import { buttonShowcase } from "@/components/ui/button.showcase"
+import { feedCardShowcase } from "@/components/ui/feed-card.showcase"
+import { monospaceTextShowcase } from "@/components/ui/monospace-text.showcase"
+import { sansSerifTextShowcase } from "@/components/ui/sans-serif-text.showcase"
+import { serifTextShowcase } from "@/components/ui/serif-text.showcase"
+import { type Showcase } from "@/components/showcase"
+import { SansSerifText } from "@/components/ui/sans-serif-text"
+
+const showcases: Record<string, Showcase> = {
+	button: buttonShowcase,
+	"feed-card": feedCardShowcase,
+	"serif-text": serifTextShowcase,
+	"sans-serif-text": sansSerifTextShowcase,
+	"monospace-text": monospaceTextShowcase,
+}
+
+export default function ComponentDetailScreen() {
+	const { name } = useLocalSearchParams<{ name: string }>()
+	const navigation = useNavigation()
+	const showcase = showcases[name]
+
+	useEffect(() => {
+		if (showcase) {
+			navigation.setOptions({ title: showcase.title })
+		}
+	}, [navigation, showcase])
+
+	if (!showcase) {
+		return (
+			<View style={tw`bg-stone-100 dark:bg-stone-900 flex-1 items-center justify-center`}>
+				<SansSerifText>Component not found</SansSerifText>
+			</View>
+		)
+	}
+
+	const ShowcaseComponent = showcase.component
+
+	return (
+		<ScrollView style={tw`bg-stone-100 dark:bg-stone-900 flex-1`} contentContainerStyle={tw`px-5 pb-10 pt-4 gap-6`}>
+			<ShowcaseComponent />
+		</ScrollView>
+	)
+}