feat(mobile): fondation design system DSFR (theme + composants UI) + hooks admin + route admin

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

mobile/components/ui/Loader.tsx

@@ -0,0 +1,18 @@
+import { ActivityIndicator, StyleSheet, Text, View } from 'react-native';
+import { Colors } from '@/lib/colors';
+import { FontSize, Spacing } from '@/lib/theme';
+
+/** Indicateur de chargement centré et homogène, avec libellé optionnel. */
+export default function Loader({ label }: { label?: string }) {
+  return (
+    <View style={styles.container}>
+      <ActivityIndicator size="large" color={Colors.primary} />
+      {label ? <Text style={styles.label}>{label}</Text> : null}
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: { flex: 1, alignItems: 'center', justifyContent: 'center', padding: Spacing.xl, backgroundColor: Colors.gray[50] },
+  label: { marginTop: Spacing.md, fontSize: FontSize.sm, color: Colors.gray[500] },
+});