implement Clean Architecture and user authentication

- Add LoopFit.Domain with entities (ApplicationUser, Workout, CalorieEntry, VitalData), enums (WorkoutType), and interfaces (IJwtTokenGenerator, IUserRepository, IWorkoutRepository)
- Add LoopFit.Application with auth DTOs, service interfaces, and DI setup
- Add LoopFit.Infrastructure with EF Core DbContext (PostgreSQL), ASP.NET Core Identity, JWT token generation, and repository implementations
- Add AuthController with register/login/me endpoints and JWT Bearer auth
- Add MAUI auth services (AuthService, TokenStorageService) and Login/Register Blazor pages

LoopFit/wwwroot/app.css

@@ -1,3 +1,41 @@
+html, body {
+    font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
+}
+
+a, .btn-link {
+    color: #006bb7;
+}
+
+.btn-primary {
+    color: #fff;
+    background-color: #1b6ec2;
+    border-color: #1861ac;
+}
+
+.btn:focus, .btn:active:focus, .btn-link.nav-link:focus, .form-control:focus, .form-check-input:focus {
+  box-shadow: 0 0 0 0.1rem white, 0 0 0 0.25rem #258cfb;
+}
+
+.content {
+    padding-top: 1.1rem;
+}
+
+h1:focus {
+    outline: none;
+}
+
+.valid.modified:not([type=checkbox]) {
+    outline: 1px solid #26b050;
+}
+
+.invalid {
+    outline: 1px solid #e50000;
+}
+
+.validation-message {
+    color: #e50000;
+}
+
 .status-bar-safe-area {
     display: none;
 }

LoopFit/wwwroot/index.html

@@ -5,8 +5,7 @@
     <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no, viewport-fit=cover" />
     <title>LoopFit</title>
     <base href="/" />
-    <link rel="stylesheet" href="_content/LoopFit.Shared/lib/bootstrap/dist/css/bootstrap.min.css" />
-    <link rel="stylesheet" href="_content/LoopFit.Shared/app.css" />
+    <link rel="stylesheet" href="lib/bootstrap/dist/css/bootstrap.min.css" />
     <link rel="stylesheet" href="app.css" />
     <link rel="stylesheet" href="LoopFit.styles.css" />
     <link rel="icon" href="data:,">
@@ -22,4 +21,4 @@
 
 </body>
 
-</html>
+</html>