feat: implement add-task MCP command

- Create direct function wrapper in add-task.js with prompt and dependency handling

- Add MCP tool integration for creating new tasks via AI

- Update task-master-core.js to expose addTaskDirect function

- Update changeset to document the new command

mcp-server/src/core/direct-functions/add-task.js

@@ -0,0 +1,67 @@
+/**
+ * add-task.js
+ * Direct function implementation for adding a new task
+ */
+
+import { addTask } from '../../../../scripts/modules/task-manager.js';
+import { findTasksJsonPath } from '../utils/path-utils.js';
+
+/**
+ * Direct function wrapper for adding a new task with error handling.
+ *
+ * @param {Object} args - Command arguments
+ * @param {string} args.prompt - Description of the task to add
+ * @param {Array<number>} [args.dependencies=[]] - Task dependencies as array of IDs
+ * @param {string} [args.priority='medium'] - Task priority (high, medium, low)
+ * @param {string} [args.file] - Path to the tasks file
+ * @param {string} [args.projectRoot] - Project root directory
+ * @param {Object} log - Logger object
+ * @returns {Promise<Object>} - Result object { success: boolean, data?: any, error?: { code: string, message: string } }
+ */
+export async function addTaskDirect(args, log) {
+  try {
+    // Resolve the tasks file path
+    const tasksPath = findTasksJsonPath(args.file, args.projectRoot);
+    
+    // Check required parameters
+    if (!args.prompt) {
+      log.error('Missing required parameter: prompt');
+      return {
+        success: false,
+        error: {
+          code: 'MISSING_PARAMETER',
+          message: 'The prompt parameter is required for adding a task'
+        }
+      };
+    }
+    
+    // Extract and prepare parameters
+    const prompt = args.prompt;
+    const dependencies = Array.isArray(args.dependencies) 
+      ? args.dependencies 
+      : (args.dependencies ? String(args.dependencies).split(',').map(id => parseInt(id.trim(), 10)) : []);
+    const priority = args.priority || 'medium';
+    
+    log.info(`Adding new task with prompt: "${prompt}", dependencies: [${dependencies.join(', ')}], priority: ${priority}`);
+    
+    // Call the addTask function
+    const newTaskId = await addTask(tasksPath, prompt, dependencies, priority);
+    
+    return {
+      success: true,
+      data: {
+        taskId: newTaskId,
+        message: `Successfully added new task #${newTaskId}`
+      }
+    };
+  } catch (error) {
+    log.error(`Error in addTaskDirect: ${error.message}`);
+    return {
+      success: false,
+      error: {
+        code: 'ADD_TASK_ERROR',
+        message: error.message
+      }
+    };
+  }
+}