Release version 0.2.0

[cyou1314]

What changed

• Bump the package and runtime version from 0.1.4 to 0.2.0.
• Mark the completed workflow, prompt-pack, QC-report, and runtime-handoff work as the 0.2.0 changelog entry.
• Update the README version reference.
• Add a regression test that keeps pyproject.toml and aigc_director_kit.__version__ synchronized.

Why

PR #2 added multiple public contracts and CLI capabilities. This is a minor, backward-compatible feature release rather than a patch-only change.

Validation

• 30 unittest cases passed.
• Editable installation reports version 0.2.0 for both package metadata and runtime.
• Windows run_examples.bat passed.
• Public JSON/schema parsing, compileall, and git diff --check passed.

No GitHub release tag was created yet; this PR only updates the repository version metadata.