feat: add version flag to CLI entry points

[Jiya3177]

Summary

Add --version support to both CLI entry points.

Related Issue

Fixes #25

Type of Change

• Bug fix
• New feature
• Documentation
• Refactoring
• Test changes
• CI/Chore

Testing

• uv run ruff check passes
• uv run mypy passes
• uv run pytest passes
• Manual testing done

Manual testing:

• PYTHONPATH=src python3 -m pytest tests/cli/test_new_cli.py::test_typer_app_version_option tests/cli/test_oss_commands.py::test_main_version_option
• python3 -m ruff check main.py src/oss_dev/cli/app.py tests/cli/test_new_cli.py tests/cli/test_oss_commands.py

Note: Running the broader CLI test file still shows unrelated existing environment/config failures around missing Gemini API key.

Description

Added Click --version / -V support to the top-level oss-dev CLI using the shared version string from src/oss_dev/_version.py.

Verified the Typer oss-dev-new CLI already uses the same shared version string and added test coverage for it.

Both entry points now print:

oss-dev v0.2.0

and exit cleanly without requiring config or API keys.

[Hell1213]

Review: version flag for CLI entry points

Hi @Jiya3177, this looks good.

Verified:

• Tests pass (74/74, including 2 new version tests)
• Ruff checks clean
• No circular import risk (oss_dev._version is a standalone module)

Changes look correct:

• oss-dev --version prints oss-dev v0.2.0 via Click version_option
• oss-dev-new --version works via Typer callback (already existed)
• Both use shared version from oss_dev._version

Approving this PR.