feat: Implement OAuth2 authentication with Microsoft, Google, and PocketId

- Added JWT configuration to appsettings.json for secure token handling.
- Updated config.json to include OAuth provider details for Microsoft, Google, and PocketId.
- Added Microsoft icon SVG for UI representation.
- Refactored app.config.ts to use a custom AuthInterceptor for managing access tokens.
- Enhanced auth route guard to handle asynchronous authentication checks.
- Created new auth models for structured request and response handling.
- Developed a callback component to manage user login states and transitions.
- Updated side-login component to support multiple OAuth providers with loading states.
- Implemented authentication service methods for handling OAuth login flows and token management.
- Added error handling and user feedback for authentication processes.

Api/Models/AppDbContext.cs

@@ -14,12 +14,40 @@ namespace Api.Models
     {
         public AppDbContext(DbContextOptions<AppDbContext> options) : base(options) { }
         public DbSet<Product> Products { get; set; }
-
         public DbSet<WebMessage> WebMessages { get; set; }
+        public DbSet<User> Users { get; set; }
+        public DbSet<UserOAuthProvider> UserOAuthProviders { get; set; }
 
         protected override void OnModelCreating(ModelBuilder modelBuilder)
         {
             base.OnModelCreating(modelBuilder);
+            
+            // Configure User entity
+            modelBuilder.Entity<User>(entity =>
+            {
+                entity.HasKey(e => e.Id);
+                entity.HasIndex(e => e.Email).IsUnique();
+                entity.Property(e => e.Email).IsRequired().HasMaxLength(255);
+                entity.Property(e => e.FirstName).HasMaxLength(255);
+                entity.Property(e => e.LastName).HasMaxLength(255);
+                entity.Property(e => e.ProfilePictureUrl).HasMaxLength(500);
+            });
+            
+            // Configure UserOAuthProvider entity
+            modelBuilder.Entity<UserOAuthProvider>(entity =>
+            {
+                entity.HasKey(e => e.Id);
+                entity.HasIndex(e => new { e.Provider, e.ProviderId }).IsUnique();
+                entity.Property(e => e.ProviderId).IsRequired().HasMaxLength(255);
+                entity.Property(e => e.ProviderEmail).HasMaxLength(255);
+                entity.Property(e => e.ProviderName).HasMaxLength(255);
+                
+                entity.HasOne(e => e.User)
+                    .WithMany(u => u.OAuthProviders)
+                    .HasForeignKey(e => e.UserId)
+                    .OnDelete(DeleteBehavior.Cascade);
+            });
+            
             // Seed data
             modelBuilder.Entity<Product>().HasData(
                 new Product { Id = 1, Name = "Sample Product", Price = 9.99M }