phase3(critical-path): store + main + routes + nav components null-safe

- store/state + reducers: nullable AppState fields & reducer types
- main.dart: localeResolutionCallback Locale?, settings.name? guard
- routes.dart: fluro 2.0.5 HandlerFunc (BuildContext?) + params['x']!
- navigationbar/breadcrumbs/bottom_nav/text_link: nullable optional params/fields

lib/widgets/general/text_link.dart

@@ -11,22 +11,22 @@ import '../../routes.dart';
 class TextLink extends StatelessWidget {
   final String title;
   final String url;
-  final Color color;
-  final Color hoverColor;
-  final double paddingHorizontal;
-  final double paddingVertical;
-  final FontWeight fontWeight;
-  final bool selected;
+  final Color? color;
+  final Color? hoverColor;
+  final double? paddingHorizontal;
+  final double? paddingVertical;
+  final FontWeight? fontWeight;
+  final bool? selected;
   final bool isLink;
   final bool replace;
   final bool clearStack;
   final bool maintainState;
   final bool rootNavigator;
-  final TransitionType transition;
+  final TransitionType? transition;
   final bool closeDrawer;
   final bool isEmail;
   final bool isPhone;
-  final double fontSize;
+  final double? fontSize;
   final bool isAddress;
   final TextOverflow overflow;
   final int maxLines;
@@ -38,19 +38,19 @@ class TextLink extends StatelessWidget {
     this.paddingVertical,
     this.fontWeight,
     this.selected,
-    bool isLink,
-    bool replace,
-    bool clearStack,
-    bool maintainState,
-    bool rootNavigator,
+    bool? isLink,
+    bool? replace,
+    bool? clearStack,
+    bool? maintainState,
+    bool? rootNavigator,
     this.transition,
-    bool closeDrawer,
-    bool isEmail,
-    bool isPhone,
-    double fontSize,
-    bool isAddress,
-    TextOverflow overflow,
-    int maxLines,
+    bool? closeDrawer,
+    bool? isEmail,
+    bool? isPhone,
+    double? fontSize,
+    bool? isAddress,
+    TextOverflow? overflow,
+    int? maxLines,
   }) :
         isLink = isLink ?? false,
         replace = replace ?? false,
@@ -60,7 +60,7 @@ class TextLink extends StatelessWidget {
         closeDrawer = closeDrawer ?? false,
         isEmail = isEmail ?? false,
         isPhone = isPhone ?? false,
-        fontSize = fontSize ?? null,
+        fontSize = fontSize,
         isAddress = isAddress ?? false,
         overflow = overflow ?? TextOverflow.ellipsis,
         maxLines = maxLines ?? 1;
@@ -101,7 +101,7 @@ class TextLink extends StatelessWidget {
             },
           ),
           decoration: BoxDecoration(
-            border: (selected != null && selected) ? Border(
+            border: (selected == true) ? Border(
                 bottom: BorderSide(
                   color: color ?? Colors.blue,
                   width: 3.0,
@@ -110,7 +110,7 @@ class TextLink extends StatelessWidget {
           ),
         ),
         onTap: () async {
-          if (selected == null || !selected) {
+          if (selected != true) {
             if (isEmail) {
               Utils.openEmail(url);
             } else if (isPhone) {