Fix missing config bootstrap

[sureshchouksey8]

Summary

• Create ~/.config/task-cli/config.yaml from config.yaml.example when it is missing.
• Keep config path resolution in a helper so first-run behavior is testable.
• Update README configuration guidance to describe the automatic bootstrap.

Verification

• python3 -m pytest -q test_task.py - 3 passed
• python3 -m py_compile task.py commands/*.py test_task.py
• git diff --check

/claim #2