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/User.cs

@@ -0,0 +1,72 @@
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+
+namespace Api.Models
+{
+    public class User
+    {
+        [Key]
+        public int Id { get; set; }
+        
+        [Required]
+        [StringLength(255)]
+        public string Email { get; set; } = string.Empty;
+        
+        [StringLength(255)]
+        public string? FirstName { get; set; }
+        
+        [StringLength(255)]
+        public string? LastName { get; set; }
+        
+        [StringLength(500)]
+        public string? ProfilePictureUrl { get; set; }
+        
+        [Required]
+        public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+        
+        public DateTime? LastLoginAt { get; set; }
+        
+        public bool IsActive { get; set; } = true;
+        
+        // Navigation property for OAuth providers
+        public virtual ICollection<UserOAuthProvider> OAuthProviders { get; set; } = new List<UserOAuthProvider>();
+    }
+    
+    public class UserOAuthProvider
+    {
+        [Key]
+        public int Id { get; set; }
+        
+        [Required]
+        public int UserId { get; set; }
+        
+        [Required]
+        public OAuthProvider Provider { get; set; }
+        
+        [Required]
+        [StringLength(255)]
+        public string ProviderId { get; set; } = string.Empty;
+        
+        [StringLength(255)]
+        public string? ProviderEmail { get; set; }
+        
+        [StringLength(255)]
+        public string? ProviderName { get; set; }
+        
+        public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
+        
+        public DateTime? LastUsedAt { get; set; }
+        
+        // Navigation property
+        [ForeignKey("UserId")]
+        public virtual User User { get; set; } = null!;
+    }
+    
+    public enum OAuthProvider
+    {
+        Microsoft = 1,
+        Google = 2,
+        PocketId = 3
+        // Add more providers as needed
+    }
+}