feat: add get_version() helper function

[haosenwang1018]

Summary

Add get_version() helper function to retrieve package version.

Changes

• Add get_version() function to return version
• Useful for CLI and programmatic version checks

Testing

• Function returns correct version string
• No breaking changes

[dippatel1994]

Hi @haosenwang1018, thanks for your contribution. Could you please create an issue and link it here? Also, add a small test for this change.

[dippatel1994]

Hey @haosenwang1018, paperbanana.__version__ is already exported from the package, so a get_version() helper adds minimal value as a standalone. This overlaps with PR #29 which exposes version on the CLI. Would you like to close this and let #29 cover version exposure, or expand this PR to add the CLI --version flag as well?