feat: add Flutter mobile clients and staff delivery API

apps/user_app/analysis_options.yaml

@@ -0,0 +1,16 @@
+include: package:flutter_lints/flutter.yaml
+
+analyzer:
+  language:
+    strict-casts: true
+    strict-inference: true
+    strict-raw-types: true
+
+linter:
+  rules:
+    avoid_print: true
+    use_super_parameters: true
+
+formatter:
+  page_width: 100
+  trailing_commas: preserve