refactor(mcp): Enforce projectRoot and centralize path validation

This commit refactors how project paths are handled in MCP direct functions to improve reliability, particularly when session context is incomplete or missing.

Key changes: 1) Made projectRoot required in MCP tools. 2) Refactored findTasksJsonPath to return {tasksPath, validatedProjectRoot}. 3) Updated all direct functions to pass session to findTasksJsonPath. 4) Updated analyzeTaskComplexityDirect to use the validated root for output path resolution.

This ensures operations relying on project context receive an explicitly provided and validated project root directory, resolving errors caused by incorrect path resolution.

scripts/init.js

@@ -909,7 +909,7 @@ function setupMCPConfiguration(targetDir, projectName) {
 	const newMCPServer = {
 		'task-master-ai': {
 			command: 'npx',
-			args: ['-y', '--package', 'task-master-ai', 'task-master-mcp'],
+			args: ['-y', 'task-master-mcp'],
 			env: {
 				ANTHROPIC_API_KEY: '%ANTHROPIC_API_KEY%',
 				PERPLEXITY_API_KEY: '%PERPLEXITY_API_KEY%',