phase3: stabilize nullfix.py (disable risky local-nullable handler)

Script stable handlers (zero corruption): bang(!), late, param-nullable,
field-formal field-nullable, arg-bang. Reusable — re-run after manual fixes.
Errors: 2374(peak) -> 596 | web build: 1845 -> 571

lib/pages/blog.dart

@@ -11,7 +11,7 @@ class Blog extends StatelessWidget {
   final Key? key;
   final int businessId;
 
-  const Blog({this.key, int businessId}) :
+  const Blog({this.key, int? businessId}) :
       businessId = businessId ?? Constants.BUSINESS_ID;
 
   @override

lib/pages/edit_address.dart

@@ -16,7 +16,7 @@ class EditAddress extends StatelessWidget {
   final Key? key;
   final Address address;
   final int businessId;
-  const EditAddress(this.address, {this.key, int businessId}) :
+  const EditAddress(this.address, {this.key, int? businessId}) :
       businessId = businessId ?? Constants.BUSINESS_ID;
 
   @override

lib/pages/my_addresses.dart

@@ -11,7 +11,7 @@ class MyAddresses extends StatelessWidget {
   final Key? key;
   final int businessId;
 
-  const MyAddresses({this.key, int businessId}) :
+  const MyAddresses({this.key, int? businessId}) :
       businessId = businessId ?? Constants.BUSINESS_ID;
 
   @override

lib/pages/my_support.dart

@@ -11,7 +11,7 @@ class MySupport extends StatelessWidget {
   final Key? key;
   final int businessId;
 
-  const MySupport({this.key, int businessId}) :
+  const MySupport({this.key, int? businessId}) :
       businessId = businessId ?? Constants.BUSINESS_ID;
 
   @override

lib/pages/new_ticket.dart

@@ -17,7 +17,7 @@ class NewTicket extends StatefulWidget {
   final Key? key;
   final int businessId;
 
-  const NewTicket({this.key, int businessId}) :
+  const NewTicket({this.key, int? businessId}) :
         businessId = businessId ?? Constants.BUSINESS_ID;
 
   @override