fix: use tag-specific complexity reports (#857)

* fix(expand-task): Use tag-specific complexity reports

- Add getTagAwareFilePath utility function to resolve tag-specific file paths
- Update expandTask to use tag-aware complexity report paths
- Fix issue where expand-task always used default complexity report
- Add comprehensive tests for getTagAwareFilePath utility
- Ensure proper handling of file extensions and directory structures

Fixes #850: Expanding tasks not using tag-specific complexity reports

The expandTask function now correctly uses complexity reports specific
to the current tag context (e.g., task-complexity-report_feature-branch.json)
instead of always using the default task-complexity-report.json file.

This enables proper task expansion behavior when working with multiple
tag contexts, ensuring complexity analysis is tag-specific and accurate.

* chore: Add changeset for tag-specific complexity reports fix

* test(expand-task): Add tests for tag-specific complexity report integration

- Introduced a new test suite for verifying the integration of tag-specific complexity reports in the expandTask function.
- Added a test case to ensure the correct complexity report is used when available for a specific tag.
- Mocked file system interactions to simulate the presence of tag-specific complexity reports.

This enhances the test coverage for task expansion behavior, ensuring it accurately reflects the complexity analysis based on the current tag context.

* refactor(task-manager): unify and simplify tag-aware file path logic and tests

- Reformatted imports and cleaned up comments in test files for readability
- Centralized mocks: moved getTagAwareFilePath & slugifyTagForFilePath
  mocks to setup.js for consistency and maintainability
- Simplified utils/getTagAwareFilePath: replaced manual parsing with
  path.parse() & path.format(); improved extension handling
- Enhanced test mocks for path.parse, path.format & reset path.join
  in beforeEach to avoid interference
- All tests now pass consistently; no change in functionality

scripts/modules/task-manager/expand-task.js

@@ -2,7 +2,13 @@ import fs from 'fs';
 import path from 'path';
 import { z } from 'zod';
 
-import { log, readJSON, writeJSON, isSilentMode } from '../utils.js';
+import {
+	log,
+	readJSON,
+	writeJSON,
+	isSilentMode,
+	getTagAwareFilePath
+} from '../utils.js';
 
 import {
 	startLoadingIndicator,
@@ -497,9 +503,18 @@ async function expandTask(
 		let complexityReasoningContext = '';
 		let systemPrompt; // Declare systemPrompt here
 
-		const complexityReportPath = path.join(projectRoot, COMPLEXITY_REPORT_FILE);
+		// Use tag-aware complexity report path
+		const complexityReportPath = getTagAwareFilePath(
+			COMPLEXITY_REPORT_FILE,
+			tag,
+			projectRoot
+		);
 		let taskAnalysis = null;
 
+		logger.info(
+			`Looking for complexity report at: ${complexityReportPath}${tag && tag !== 'master' ? ` (tag-specific for '${tag}')` : ''}`
+		);
+
 		try {
 			if (fs.existsSync(complexityReportPath)) {
 				const complexityReport = readJSON(complexityReportPath);