fix(backend): Fix MCP module compilation errors by using correct exception classes

Replaced non-existent ColaFlow.Shared.Kernel.Exceptions namespace references
with ColaFlow.Modules.Mcp.Domain.Exceptions in 5 files:

Changes:
- McpToolRegistry.cs: Use McpInvalidParamsException and McpNotFoundException
- AddCommentTool.cs: Use McpInvalidParamsException and McpNotFoundException
- CreateIssueTool.cs: Use McpInvalidParamsException, McpNotFoundException, and ProjectId.From()
- UpdateStatusTool.cs: Use McpNotFoundException
- ToolParameterParser.cs: Use McpInvalidParamsException for all validation errors

All BadRequestException -> McpInvalidParamsException
All NotFoundException -> McpNotFoundException

Also fixed CreateIssueTool to convert Guid to ProjectId value object.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Contracts/Tools/IMcpTool.cs

@@ -0,0 +1,49 @@
+namespace ColaFlow.Modules.Mcp.Contracts.Tools;
+
+/// <summary>
+/// Interface for MCP Tools
+/// Tools provide write operations to AI agents through the MCP protocol
+/// All write operations create PendingChanges and require human approval
+/// </summary>
+public interface IMcpTool
+{
+    /// <summary>
+    /// Tool name (e.g., "create_issue", "update_status")
+    /// Must be unique and follow snake_case naming convention
+    /// </summary>
+    string Name { get; }
+
+    /// <summary>
+    /// Human-readable tool description for AI to understand when to use this tool
+    /// </summary>
+    string Description { get; }
+
+    /// <summary>
+    /// JSON Schema describing the tool's input parameters
+    /// </summary>
+    McpToolInputSchema InputSchema { get; }
+
+    /// <summary>
+    /// Execute the tool with the provided arguments
+    /// This should create a PendingChange, NOT execute the change directly
+    /// </summary>
+    /// <param name="toolCall">The tool call request with arguments</param>
+    /// <param name="cancellationToken">Cancellation token</param>
+    /// <returns>Tool execution result</returns>
+    Task<McpToolResult> ExecuteAsync(
+        McpToolCall toolCall,
+        CancellationToken cancellationToken);
+
+    /// <summary>
+    /// Get tool descriptor with full metadata
+    /// </summary>
+    McpToolDescriptor GetDescriptor()
+    {
+        return new McpToolDescriptor
+        {
+            Name = Name,
+            Description = Description,
+            InputSchema = InputSchema
+        };
+    }
+}

colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Contracts/Tools/McpToolCall.cs

@@ -0,0 +1,18 @@
+namespace ColaFlow.Modules.Mcp.Contracts.Tools;
+
+/// <summary>
+/// Represents a tool call request from an AI agent
+/// </summary>
+public sealed class McpToolCall
+{
+    /// <summary>
+    /// Tool name to execute
+    /// </summary>
+    public string Name { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Tool arguments as key-value pairs
+    /// Values can be strings, numbers, booleans, arrays, or objects
+    /// </summary>
+    public Dictionary<string, object> Arguments { get; set; } = new();
+}

colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Contracts/Tools/McpToolDescriptor.cs

@@ -0,0 +1,22 @@
+namespace ColaFlow.Modules.Mcp.Contracts.Tools;
+
+/// <summary>
+/// Descriptor for an MCP Tool containing metadata and schema
+/// </summary>
+public sealed class McpToolDescriptor
+{
+    /// <summary>
+    /// Tool name
+    /// </summary>
+    public string Name { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Tool description
+    /// </summary>
+    public string Description { get; set; } = string.Empty;
+
+    /// <summary>
+    /// Input parameter schema
+    /// </summary>
+    public McpToolInputSchema InputSchema { get; set; } = new();
+}

colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Contracts/Tools/McpToolInputSchema.cs

@@ -0,0 +1,89 @@
+namespace ColaFlow.Modules.Mcp.Contracts.Tools;
+
+/// <summary>
+/// JSON Schema for tool input parameters
+/// </summary>
+public sealed class McpToolInputSchema
+{
+    /// <summary>
+    /// Schema type (always "object" for tool inputs)
+    /// </summary>
+    public string Type { get; set; } = "object";
+
+    /// <summary>
+    /// Schema properties (parameter definitions)
+    /// Key is parameter name, value is parameter schema
+    /// </summary>
+    public Dictionary<string, JsonSchemaProperty> Properties { get; set; } = new();
+
+    /// <summary>
+    /// List of required parameter names
+    /// </summary>
+    public List<string> Required { get; set; } = new();
+}
+
+/// <summary>
+/// JSON Schema property definition
+/// </summary>
+public sealed class JsonSchemaProperty
+{
+    /// <summary>
+    /// Property type: "string", "number", "integer", "boolean", "array", "object"
+    /// </summary>
+    public string Type { get; set; } = "string";
+
+    /// <summary>
+    /// Property description (for AI to understand)
+    /// </summary>
+    public string? Description { get; set; }
+
+    /// <summary>
+    /// Enum values (for restricted choices)
+    /// </summary>
+    public string[]? Enum { get; set; }
+
+    /// <summary>
+    /// String format hint: "uuid", "email", "date-time", "uri", etc.
+    /// </summary>
+    public string? Format { get; set; }
+
+    /// <summary>
+    /// Minimum value (for numbers)
+    /// </summary>
+    public decimal? Minimum { get; set; }
+
+    /// <summary>
+    /// Maximum value (for numbers)
+    /// </summary>
+    public decimal? Maximum { get; set; }
+
+    /// <summary>
+    /// Minimum length (for strings)
+    /// </summary>
+    public int? MinLength { get; set; }
+
+    /// <summary>
+    /// Maximum length (for strings)
+    /// </summary>
+    public int? MaxLength { get; set; }
+
+    /// <summary>
+    /// Pattern (regex) for string validation
+    /// </summary>
+    public string? Pattern { get; set; }
+
+    /// <summary>
+    /// Items schema (for arrays)
+    /// </summary>
+    public JsonSchemaProperty? Items { get; set; }
+
+    /// <summary>
+    /// Properties schema (for nested objects)
+    /// </summary>
+    public Dictionary<string, JsonSchemaProperty>? Properties { get; set; }
+
+    /// <summary>
+    /// Default value
+    /// </summary>
+    public object? Default { get; set; }
+}

colaflow-api/src/Modules/Mcp/ColaFlow.Modules.Mcp.Contracts/Tools/McpToolResult.cs

@@ -0,0 +1,38 @@
+namespace ColaFlow.Modules.Mcp.Contracts.Tools;
+
+/// <summary>
+/// Result of a tool execution
+/// </summary>
+public sealed class McpToolResult
+{
+    /// <summary>
+    /// Tool result content (typically text describing the PendingChange created)
+    /// </summary>
+    public IEnumerable<McpToolContent> Content { get; set; } = Array.Empty<McpToolContent>();
+
+    /// <summary>
+    /// Whether the tool execution failed
+    /// </summary>
+    public bool IsError { get; set; }
+}
+
+/// <summary>
+/// Content item in a tool result
+/// </summary>
+public sealed class McpToolContent
+{
+    /// <summary>
+    /// Content type: "text" or "resource"
+    /// </summary>
+    public string Type { get; set; } = "text";
+
+    /// <summary>
+    /// Text content (for type="text")
+    /// </summary>
+    public string? Text { get; set; }
+
+    /// <summary>
+    /// Resource URI (for type="resource")
+    /// </summary>
+    public string? Resource { get; set; }
+}