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/Services/JwtService.cs

@@ -0,0 +1,139 @@
+using Api.Models;
+using Api.Models.DTOs;
+using Microsoft.IdentityModel.Tokens;
+using System.IdentityModel.Tokens.Jwt;
+using System.Security.Claims;
+using System.Text;
+
+namespace Api.Services
+{
+    public interface IJwtService
+    {
+        string GenerateToken(User user);
+        ClaimsPrincipal? ValidateToken(string token);
+        DateTime GetTokenExpiration(string token);
+    }
+    
+    public class JwtService : IJwtService
+    {
+        private readonly JwtSettings _jwtSettings;
+        private readonly ILogger<JwtService> _logger;
+        private readonly SymmetricSecurityKey _key;
+        
+        public JwtService(IConfiguration configuration, ILogger<JwtService> logger)
+        {
+            _jwtSettings = configuration.GetSection("Jwt").Get<JwtSettings>() 
+                ?? throw new InvalidOperationException("JWT settings not configured");
+            _logger = logger;
+            _key = new SymmetricSecurityKey(Encoding.UTF8.GetBytes(_jwtSettings.SecretKey));
+        }
+        
+        public string GenerateToken(User user)
+        {
+            try
+            {
+                var tokenHandler = new JwtSecurityTokenHandler();
+                var credentials = new SigningCredentials(_key, SecurityAlgorithms.HmacSha256);
+                
+                var claims = new List<Claim>
+                {
+                    new Claim(ClaimTypes.NameIdentifier, user.Id.ToString()),
+                    new Claim(ClaimTypes.Email, user.Email),
+                    new Claim("jti", Guid.NewGuid().ToString()),
+                    new Claim("iat", DateTimeOffset.UtcNow.ToUnixTimeSeconds().ToString(), ClaimValueTypes.Integer64)
+                };
+                
+                // Add optional claims if available
+                if (!string.IsNullOrEmpty(user.FirstName))
+                {
+                    claims.Add(new Claim(ClaimTypes.GivenName, user.FirstName));
+                }
+                
+                if (!string.IsNullOrEmpty(user.LastName))
+                {
+                    claims.Add(new Claim(ClaimTypes.Surname, user.LastName));
+                }
+                
+                // Add provider information
+                var providers = user.OAuthProviders.Select(p => p.Provider.ToString()).ToList();
+                if (providers.Any())
+                {
+                    claims.Add(new Claim("providers", string.Join(",", providers)));
+                }
+                
+                var tokenDescriptor = new SecurityTokenDescriptor
+                {
+                    Subject = new ClaimsIdentity(claims),
+                    Expires = DateTime.UtcNow.AddMinutes(_jwtSettings.ExpirationMinutes),
+                    SigningCredentials = credentials,
+                    Issuer = _jwtSettings.Issuer,
+                    Audience = _jwtSettings.Audience
+                };
+                
+                var token = tokenHandler.CreateToken(tokenDescriptor);
+                return tokenHandler.WriteToken(token);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error generating JWT token for user {UserId}", user.Id);
+                throw new InvalidOperationException("Failed to generate access token", ex);
+            }
+        }
+        
+        public ClaimsPrincipal? ValidateToken(string token)
+        {
+            try
+            {
+                var tokenHandler = new JwtSecurityTokenHandler();
+                
+                var validationParameters = new TokenValidationParameters
+                {
+                    ValidateIssuerSigningKey = true,
+                    IssuerSigningKey = _key,
+                    ValidateIssuer = true,
+                    ValidIssuer = _jwtSettings.Issuer,
+                    ValidateAudience = true,
+                    ValidAudience = _jwtSettings.Audience,
+                    ValidateLifetime = true,
+                    ClockSkew = TimeSpan.FromMinutes(5) // Allow 5 minutes clock skew
+                };
+                
+                var principal = tokenHandler.ValidateToken(token, validationParameters, out var validatedToken);
+                
+                // Ensure the token is a JWT token with the correct algorithm
+                if (validatedToken is not JwtSecurityToken jwtToken || 
+                    !jwtToken.Header.Alg.Equals(SecurityAlgorithms.HmacSha256, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    return null;
+                }
+                
+                return principal;
+            }
+            catch (SecurityTokenException ex)
+            {
+                _logger.LogWarning(ex, "Invalid token validation attempt");
+                return null;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error validating JWT token");
+                return null;
+            }
+        }
+        
+        public DateTime GetTokenExpiration(string token)
+        {
+            try
+            {
+                var tokenHandler = new JwtSecurityTokenHandler();
+                var jsonToken = tokenHandler.ReadJwtToken(token);
+                return jsonToken.ValidTo;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error reading token expiration");
+                throw new InvalidOperationException("Invalid token format", ex);
+            }
+        }
+    }
+}