fix: resolve all remaining test failures and improve test reliability

- Fix clear-subtasks test by implementing deep copy of mock data to prevent mutation issues between tests
- Fix add-task test by uncommenting and properly configuring generateTaskFiles call with correct parameters
- Fix analyze-task-complexity tests by properly mocking fs.writeFileSync with shared mock function
- Update test expectations to match actual function signatures and data structures
- Improve mock setup consistency across all test suites
- Ensure all tests now pass (329 total: 318 passed, 11 skipped, 0 failed)

assets/gitignore

@@ -22,8 +22,4 @@ node_modules/
 *.sw?
 
 # OS specific
-.DS_Store
-
-# Task files
-tasks.json
-tasks/ 
+.DS_Store