feat(tagged-tasks): Complete core tag management system implementation

- Implements comprehensive tagged task lists system for multi-context task management including core tag management functions (Task 103.11), MCP integration updates, and foundational infrastructure for tagged task operations. Features tag CRUD operations, validation, metadata tracking, deep task copying, and full backward compatibility.

scripts/modules/utils.js

@@ -231,9 +231,24 @@ function readJSON(filepath, projectRoot = null) {
 			filepath.includes('tasks.json')
 		) {
 			// This is legacy format - migrate to tagged format
+			// Get file creation/modification date for the master tag
+			let createdDate;
+			try {
+				const stats = fs.statSync(filepath);
+				// Use the earlier of creation time or modification time
+				createdDate =
+					stats.birthtime < stats.mtime ? stats.birthtime : stats.mtime;
+			} catch (error) {
+				// Fallback to current date if we can't get file stats
+				createdDate = new Date();
+			}
+
 			const migratedData = {
 				master: {
-					tasks: data.tasks
+					tasks: data.tasks,
+					description: 'Tasks live here by default',
+					created: createdDate.toISOString(),
+					taskCount: data.tasks ? data.tasks.length : 0
 				}
 			};
 
@@ -312,22 +327,25 @@ function readJSON(filepath, projectRoot = null) {
 					resolvedTag = 'master';
 				}
 
+				// Store the raw tagged data BEFORE modifying data
+				const rawTaggedData = { ...data };
+
 				// Return the tasks for the resolved tag, or master as fallback, or empty array
 				if (data[resolvedTag] && data[resolvedTag].tasks) {
 					data = {
 						tag: resolvedTag,
 						tasks: data[resolvedTag].tasks,
-						_rawTaggedData: data
+						_rawTaggedData: rawTaggedData
 					};
 				} else if (data.master && data.master.tasks) {
 					data = {
 						tag: 'master',
 						tasks: data.master.tasks,
-						_rawTaggedData: data
+						_rawTaggedData: rawTaggedData
 					};
 				} else {
 					// No valid tags found, return empty
-					data = { tasks: [], tag: 'master', _rawTaggedData: data };
+					data = { tasks: [], tag: 'master', _rawTaggedData: rawTaggedData };
 				}
 			}
 		}
@@ -512,7 +530,16 @@ function writeJSON(filepath, data) {
 		if (!fs.existsSync(dir)) {
 			fs.mkdirSync(dir, { recursive: true });
 		}
-		fs.writeFileSync(filepath, JSON.stringify(data, null, 2), 'utf8');
+
+		// Clean the data before writing - remove internal properties that should not be persisted
+		let cleanData = data;
+		if (data && typeof data === 'object' && data._rawTaggedData !== undefined) {
+			// Create a clean copy without internal properties using destructuring
+			const { _rawTaggedData, ...cleanedData } = data;
+			cleanData = cleanedData;
+		}
+
+		fs.writeFileSync(filepath, JSON.stringify(cleanData, null, 2), 'utf8');
 	} catch (error) {
 		log('error', `Error writing JSON file ${filepath}:`, error.message);
 		if (isDebug) {