chore: add button in settings for restore color

frontend-admin/src/screens/admin/SettingsScreen.tsx

@@ -1156,9 +1156,25 @@ function CentralRewardSection({
     );
 }
 
+// Palette violette d'origine de l'application (thème par défaut historique)
+const ORIGINAL_THEME_COLORS = {
+    admin_color_primary: "#7c3aed",
+    admin_color_secondary: "#22d3ee",
+    admin_color_success: "#4ade80",
+    admin_color_danger: "#ef4444",
+    admin_color_warning: "#f59e0b",
+    client_color_primary: "#7c3aed",
+    client_color_secondary: "#22d3ee",
+    client_color_success: "#4ade80",
+    client_color_danger: "#ef4444",
+    client_color_warning: "#f59e0b",
+    client_title_gradient_from: "#a78bfa",
+    client_title_gradient_to: "#22d3ee",
+} as const;
+
 export default function SettingsScreen() {
     const { colors, refreshColors } = useTheme();
-    const { alert, showError, showSuccess, hideAlert } = useAlert();
+    const { alert, showError, showSuccess, showConfirm, hideAlert } = useAlert();
     const navigation = useNavigation();
     const { width: screenWidth } = useWindowDimensions();
     const inputMd = screenWidth < 380 ? 64 : 80;
@@ -2271,6 +2287,36 @@ export default function SettingsScreen() {
                         Personnalisez les couleurs de l'espace admin et de l'app client / site web.
                     </Text>
 
+                    <TouchableOpacity
+                        onPress={() => showConfirm(
+                            "Restaurer le thème d'origine",
+                            "Toutes les couleurs personnalisées seront remplacées par le violet de base des premières versions de l'application. Continuer ?",
+                            () => {
+                                setSettings((p) => ({ ...p, ...ORIGINAL_THEME_COLORS }));
+                            },
+                            "Restaurer",
+                            "Annuler",
+                        )}
+                        style={{
+                            flexDirection: "row",
+                            alignItems: "center",
+                            gap: spacing.xs,
+                            marginHorizontal: spacing.l,
+                            marginTop: spacing.m,
+                            paddingVertical: spacing.s,
+                            paddingHorizontal: spacing.m,
+                            borderRadius: borderRadius.sm,
+                            borderWidth: 1,
+                            borderColor: "#7c3aed",
+                            alignSelf: "flex-start",
+                        }}
+                    >
+                        <Ionicons name="color-palette-outline" size={16} color="#7c3aed" />
+                        <Text style={{ fontSize: fontSize.sm, color: "#7c3aed", fontWeight: "600" }}>
+                            Restaurer les couleurs de base
+                        </Text>
+                    </TouchableOpacity>
+
                     {(["admin", "client"] as const).map((scope) => (
                         <View key={scope}>
                             <Text style={[s.rowLabel, { paddingHorizontal: spacing.l, paddingTop: spacing.l, paddingBottom: spacing.xs }]}>