feat(auth): transition from email to phone-based OTP authentication

- Replace Email+Password login with Phone+OTP flow
- Remove RegisterCubit and registration screens (email verification)
- Remove ResetPasswordCubit and reset password screens
- Add phone normalization and international dial code support
- Update LoginCubit with sendCode/resend cooldown logic
- Add new widgets: phone prefix selector, confirm sheet
- Update all auth API endpoints: /otp/send, /phone-session
- Update form inputs: Email -> Phone with E.164 validation
- Update tests for new auth flow

apps/lib/features/auth/ui/widgets/auth_field.dart

@@ -1,41 +1,48 @@
 import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
 
 import '../../../../core/theme/design_tokens.dart';
 
 class AuthField extends StatelessWidget {
   const AuthField({
     super.key,
-    required this.label,
+    this.label,
     required this.hint,
     required this.controller,
     this.keyboardType,
     this.obscureText = false,
     this.suffixIcon,
     this.onChanged,
+    this.prefix,
+    this.inputFormatters,
   });
 
-  final String label;
+  final String? label;
   final String hint;
   final TextEditingController controller;
   final TextInputType? keyboardType;
   final bool obscureText;
   final Widget? suffixIcon;
   final ValueChanged<String>? onChanged;
+  final Widget? prefix;
+  final List<TextInputFormatter>? inputFormatters;
 
   @override
   Widget build(BuildContext context) {
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,
       children: [
-        Text(
-          label,
-          style: const TextStyle(
-            fontSize: 13,
-            fontWeight: FontWeight.w700,
-            color: AppColors.slate700,
+        if (label != null) ...[
+          Text(
+            label!,
+            style: const TextStyle(
+              fontSize: 13,
+              fontWeight: FontWeight.w700,
+              color: AppColors.slate700,
+            ),
           ),
-        ),
-        SizedBox(height: AppSpacing.sm),
+          SizedBox(height: AppSpacing.sm),
+        ],
         Semantics(
           label: label,
           textField: true,
@@ -44,6 +51,7 @@ class AuthField extends StatelessWidget {
             keyboardType: keyboardType,
             obscureText: obscureText,
             onChanged: onChanged,
+            inputFormatters: inputFormatters,
             style: const TextStyle(fontSize: 16, color: AppColors.slate900),
             decoration: InputDecoration(
               hintText: hint,
@@ -57,6 +65,7 @@ class AuthField extends StatelessWidget {
                 horizontal: AppSpacing.lg,
                 vertical: AppSpacing.lg,
               ),
+              prefixIcon: prefix,
               suffixIcon: suffixIcon,
               border: OutlineInputBorder(
                 borderRadius: BorderRadius.circular(AppRadius.lg),

apps/lib/features/auth/ui/widgets/auth_page_scaffold.dart

@@ -9,12 +9,14 @@ class AuthPageScaffold extends StatelessWidget {
     this.footer,
     this.mainContentKey,
     this.footerKey,
+    this.resizeOnKeyboard = true,
   });
 
   final Widget mainContent;
   final Widget? footer;
   final Key? mainContentKey;
   final Key? footerKey;
+  final bool resizeOnKeyboard;
 
   @override
   Widget build(BuildContext context) {
@@ -22,6 +24,7 @@ class AuthPageScaffold extends StatelessWidget {
 
     return Scaffold(
       backgroundColor: AppColors.authBackgroundBottom,
+      resizeToAvoidBottomInset: resizeOnKeyboard,
       body: DecoratedBox(
         decoration: const BoxDecoration(
           gradient: LinearGradient(
@@ -37,8 +40,33 @@ class AuthPageScaffold extends StatelessWidget {
           children: [
             const _AuthBackgroundOrbs(),
             SafeArea(
+              maintainBottomViewPadding: !resizeOnKeyboard,
               child: LayoutBuilder(
                 builder: (context, constraints) {
+                  if (!resizeOnKeyboard) {
+                    return Padding(
+                      padding: const EdgeInsets.symmetric(
+                        horizontal: AppSpacing.lg,
+                      ),
+                      child: Center(
+                        child: Column(
+                          mainAxisSize: MainAxisSize.min,
+                          crossAxisAlignment: CrossAxisAlignment.center,
+                          children: [
+                            KeyedSubtree(
+                              key: mainContentKey,
+                              child: mainContent,
+                            ),
+                            if (footer != null) ...[
+                              SizedBox(height: AppSpacing.md),
+                              KeyedSubtree(key: footerKey, child: footer!),
+                            ],
+                          ],
+                        ),
+                      ),
+                    );
+                  }
+
                   return SingleChildScrollView(
                     keyboardDismissBehavior:
                         ScrollViewKeyboardDismissBehavior.onDrag,

apps/lib/features/auth/ui/widgets/password_field.dart

@@ -7,13 +7,13 @@ class PasswordField extends StatefulWidget {
   const PasswordField({
     super.key,
     required this.controller,
-    required this.label,
+    this.label,
     required this.hint,
     this.onChanged,
   });
 
   final TextEditingController controller;
-  final String label;
+  final String? label;
   final String hint;
   final ValueChanged<String>? onChanged;