refactor: resolve SonarQube code quality issues

- Add JWT key validation with null-check and minimum length requirement
- Fix Entity operator== to use ReferenceEquals for null comparison
- Seal HomeController and add route prefix + ProducesResponseType
- Replace Any() with Count comparisons for clarity and performance
- Convert constant arrays to static readonly fields
- Rename UserPasswordUpdateDTO to UserPasswordUpdateDto (naming convention)
- Remove unused private setters from Event model
- Remove TODO comments from placeholder controller methods

Author: alysonsz

EventFlow.Application/Behaviors/ValidationBehavior.cs

@@ -18,7 +18,9 @@ public async Task<TResponse> Handle(
         RequestHandlerDelegate<TResponse> next,
         CancellationToken cancellationToken)
     {
-        if (!_validators.Any())
+        if (_validators is ICollection<IValidator<TRequest>> validatorCollection 
+            ? validatorCollection.Count == 0 
+            : !_validators.Any())
         {
             return await next();
         }
@@ -32,7 +34,7 @@ public async Task<TResponse> Handle(
             .Where(f => f != null)
             .ToList();
 
-        if (failures.Any())
+        if (failures.Count > 0)
         {
             throw new ValidationException(failures);
         }

EventFlow.Application/DTOs/UserPasswordUpdateDTO.cs

@@ -1,6 +1,6 @@
 namespace EventFlow.Application.DTOs;
 
-public class UserPasswordUpdateDTO
+public class UserPasswordUpdateDto
 {
     public string CurrentPassword { get; set; } = string.Empty;
     public string NewPassword { get; set; } = string.Empty;

EventFlow.Application/Services/AuthService.cs

@@ -57,7 +57,7 @@ public class AuthService(
         };
     }
 
-    public async Task<bool> UpdatePasswordAsync(ClaimsPrincipal userClaims, UserPasswordUpdateDTO dto)
+    public async Task<bool> UpdatePasswordAsync(ClaimsPrincipal userClaims, UserPasswordUpdateDto dto)
     {
         var email = userClaims.FindFirstValue(ClaimTypes.Email);
         if (string.IsNullOrEmpty(email)) return false;

EventFlow.Application/Services/IAuthService.cs

@@ -7,5 +7,5 @@ public interface IAuthService
     Task<UserDTO?> RegisterAsync(RegisterUserCommand command);
     Task<string?> LoginAsync(LoginUserCommand command);
     Task<UserDTO?> GetAuthenticatedUserAsync(ClaimsPrincipal user);
-    Task<bool> UpdatePasswordAsync(ClaimsPrincipal user, UserPasswordUpdateDTO dto);
+    Task<bool> UpdatePasswordAsync(ClaimsPrincipal user, UserPasswordUpdateDto dto);
 }

EventFlow.Application/Services/RecommendationService.cs

@@ -14,14 +14,14 @@ public async Task<IEnumerable<EventDTO>> GetRecommendedEventsAsync(int participa
             ? participantWithEvents.Events.Select(e => e.Id).ToHashSet()
             : new HashSet<int>();
 
-        if (!participantEventsIds.Any())
+        if (participantEventsIds.Count == 0)
         {
             return Enumerable.Empty<EventDTO>();
         }
 
         var allParticipants = await _participantRepository.GetAllParticipantsWithEventsAsync();
         var similarParticipants = allParticipants
-            .Where(p => p.Id != participantId && (p.Events?.Any(e => participantEventsIds.Contains(e.Id)) ?? false))
+            .Where(p => p.Id != participantId && p.Events != null && p.Events.Count(e => participantEventsIds.Contains(e.Id)) > 0)
             .ToList();
 
         var recommendedEvents = similarParticipants
@@ -42,7 +42,7 @@ public async Task<IEnumerable<object>> GetRecommendedConnectionsAsync(int partic
             ? participantWithEvents.Events.Select(e => e.Id).ToHashSet()
             : new HashSet<int>();
 
-        if (!participantEventsIds.Any())
+        if (participantEventsIds.Count == 0)
         {
             return Enumerable.Empty<object>();
         }

EventFlow.Core/Models/Event.cs

@@ -7,8 +7,8 @@ public class Event : Entity<int>
     public DateTime Date { get; private set; }
     public EventLocation Location { get; private set; } = null!;
     public int OrganizerId { get; private set; }
-    public Organizer? Organizer { get; private set; }
-    public string? Category { get; private set; }
+    public Organizer? Organizer { get; init; }
+    public string? Category { get; init; }
     public ICollection<SpeakerEvent> SpeakerEvents { get; private set; } = [];
     public ICollection<Participant> Participants { get; private set; } = [];
     public DateTime CreatedAt { get; private set; }

EventFlow.Core/Primitives/Entity.cs

@@ -50,7 +50,7 @@ public override int GetHashCode()
 
     public static bool operator ==(Entity<TId>? a, Entity<TId>? b)
     {
-        if (a is null && b is null)
+        if (ReferenceEquals(a, b))
             return true;
 
         if (a is null || b is null)

EventFlow.Infrastructure/Data/EventFlowContext.cs

@@ -49,7 +49,7 @@ public override async Task<int> SaveChangesAsync(CancellationToken cancellationT
 
         var result = await base.SaveChangesAsync(cancellationToken);
 
-        if (_domainEventDispatcher != null && domainEvents.Any())
+        if (_domainEventDispatcher != null && domainEvents.Count > 0)
         {
             await _domainEventDispatcher.DispatchAsync(domainEvents, cancellationToken);
         }

EventFlow.Infrastructure/Services/JwtTokenService.cs

@@ -19,7 +19,13 @@ public JwtTokenService(IConfiguration configuration)
     public string GenerateToken(int userId, string username, string email)
     {
         var tokenHandler = new JwtSecurityTokenHandler();
-        var key = Encoding.ASCII.GetBytes(_configuration["Jwt:Key"]!);
+        var jwtKey = _configuration["Jwt:Key"] 
+            ?? throw new InvalidOperationException("JWT Key is not configured.");
+        
+        if (jwtKey.Length < 32)
+            throw new InvalidOperationException("JWT Key must be at least 32 characters long.");
+        
+        var key = Encoding.ASCII.GetBytes(jwtKey);
 
         var tokenDescriptor = new SecurityTokenDescriptor
         {
@@ -45,7 +51,13 @@ public string GenerateToken(int userId, string username, string email)
     public ClaimsPrincipal? ValidateToken(string token)
     {
         var tokenHandler = new JwtSecurityTokenHandler();
-        var key = Encoding.ASCII.GetBytes(_configuration["Jwt:Key"]!);
+        var jwtKey = _configuration["Jwt:Key"] 
+            ?? throw new InvalidOperationException("JWT Key is not configured.");
+        
+        if (jwtKey.Length < 32)
+            throw new InvalidOperationException("JWT Key must be at least 32 characters long.");
+        
+        var key = Encoding.ASCII.GetBytes(jwtKey);
 
         try
         {

EventFlow.Presentation/Config/AppConfiguration.cs

@@ -118,11 +118,14 @@ public static IServiceCollection AddRateLimitingConfig(this IServiceCollection s
         return services;
     }
 
+    private static readonly string[] DatabaseHealthTags = ["db", "sql"];
+    private static readonly string[] RedisHealthTags = ["cache", "redis"];
+
     public static IServiceCollection AddHealthCheckConfig(this IServiceCollection services, IConfiguration configuration)
     {
         services.AddHealthChecks()
-            .AddDbContextCheck<EventFlowContext>("database", failureStatus: Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus.Unhealthy, tags: new[] { "db", "sql" })
-            .AddRedis("redis", failureStatus: Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus.Degraded, tags: new[] { "cache", "redis" });
+            .AddDbContextCheck<EventFlowContext>("database", failureStatus: Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus.Unhealthy, tags: DatabaseHealthTags)
+            .AddRedis("redis", failureStatus: Microsoft.Extensions.Diagnostics.HealthChecks.HealthStatus.Degraded, tags: RedisHealthTags);
 
         services.AddHealthChecksUI(options =>
         {