feat: add password protection for channels

- Updated IChatService to include password parameter in JoinChannelAsync method.
- Modified ChannelDto and related models to support password functionality.
- Implemented password handling in ChannelService for channel creation and membership validation.
- Enhanced IrcCommandHandler to manage channel join requests with passwords.
- Added ChannelPasswordDialog for user input when joining protected channels.
- Created database migration to add PasswordHash column to Channels table.
- Updated tests to cover new password functionality in channel joining and management.

src/EchoHub.Core/Constants/ValidationConstants.cs

@@ -9,6 +9,7 @@ public static partial class ValidationConstants
     public const string HexColorPattern = @"^#[0-9a-fA-F]{6}$";
 
     public const int MaxPasswordLength = 128;
+    public const int MinChannelPasswordLength = 3;
     public const int MaxDisplayNameLength = 100;
     public const int MaxBioLength = 500;
     public const int MaxStatusMessageLength = 100;

src/EchoHub.Core/Contracts/IChannelService.cs

@@ -6,8 +6,9 @@ public interface IChannelService
 {
     // Channel CRUD
     Task<PaginatedResponse<ChannelDto>> GetChannelsAsync(Guid userId, int offset, int limit);
-    Task<ChannelOperationResult> CreateChannelAsync(Guid creatorUserId, string name, string? topic, bool isPublic);
+    Task<ChannelOperationResult> CreateChannelAsync(Guid creatorUserId, string name, string? topic, bool isPublic, string? password = null);
     Task<ChannelOperationResult> UpdateTopicAsync(Guid callerUserId, string channelName, string? topic);
+    Task<ChannelOperationResult> SetChannelPasswordAsync(Guid callerUserId, string channelName, string? password);
     Task<ChannelOperationResult> DeleteChannelAsync(Guid callerUserId, string channelName);
 
     // Channel queries
@@ -16,7 +17,7 @@ public interface IChannelService
     Task<ChannelDto?> GetChannelByNameAsync(string channelName);
 
     // Membership
-    Task<(bool Success, string? Error)> EnsureChannelMembershipAsync(Guid userId, string channelName);
+    Task<(bool Success, string? Error, bool PasswordRequired)> EnsureChannelMembershipAsync(Guid userId, string channelName, string? password = null);
 }
 
-public record ChannelListItem(string Name, string? Topic, int OnlineCount);
+public record ChannelListItem(string Name, string? Topic, int OnlineCount, bool IsPublic = true, bool IsProtected = false);

src/EchoHub.Core/Contracts/IChatService.cs

@@ -10,7 +10,7 @@ public interface IChatService
     Task<string?> UserDisconnectedAsync(string connectionId);
 
     // Channel operations
-    Task<(List<MessageDto> History, string? Error)> JoinChannelAsync(string connectionId, Guid userId, string username, string channelName);
+    Task<(List<MessageDto> History, string? Error, bool PasswordRequired)> JoinChannelAsync(string connectionId, Guid userId, string username, string channelName, string? password = null);
     Task LeaveChannelAsync(string connectionId, string username, string channelName);
 
     // Messaging

src/EchoHub.Core/DTOs/ChatDtos.cs

@@ -21,7 +21,8 @@ public record ChannelDto(
     string? Topic,
     bool IsPublic,
     int MessageCount,
-    DateTimeOffset CreatedAt);
+    DateTimeOffset CreatedAt,
+    bool IsProtected = false);
 
 public record UserDto(
     Guid Id,
@@ -33,13 +34,13 @@ public record UserDto(
 
 public record SendMessageRequest(string ChannelName, string Content);
 
-public record CreateChannelRequest(string Name, string? Topic = null, bool IsPublic = true);
+public record CreateChannelRequest(string Name, string? Topic = null, bool IsPublic = true, string? Password = null);
 
 public record UpdateTopicRequest(string? Topic);
 
 public record SendUrlRequest(string Url);
 
-public record JoinChannelResult(bool Success, List<MessageDto> History, string? Error = null);
+public record JoinChannelResult(bool Success, List<MessageDto> History, string? Error = null, bool PasswordRequired = false);
 
 public record EmbedDto(
     string? SiteName,

src/EchoHub.Core/Models/Channel.cs

@@ -6,6 +6,7 @@ public class Channel
     public required string Name { get; set; }
     public string? Topic { get; set; }
     public bool IsPublic { get; set; } = true;
+    public string? PasswordHash { get; set; }
     public DateTimeOffset CreatedAt { get; set; } = DateTimeOffset.UtcNow;
     public Guid CreatedByUserId { get; set; }