flagon-io/hello

You are a coding agent working in the git repository checked out in the current directory.

Issue #30: Add CHANGELOG.md in Keep a Changelog format with an Unreleased section

Create `CHANGELOG.md` at the repo root following https://keepachangelog.com/en/1.1.0/. Include the standard header (title `Changelog`, the note that it follows Keep a Changelog and Semantic Versioning, with links).

Add an `## [Unreleased]` section with an `### Added` list containing:
- `--shout` flag that upper-cases the greeting
- `--version` flag that prints the crate version and exits
- `--times N` flag that prints the greeting N times (default 1)

The crate version in `Cargo.toml` is 0.1.0 and nothing has been released, so do not invent a released version section. Do not modify other files.

These commands must pass when you are done. Run them if the tools are installed:
- grep -q '## \[Unreleased\]' CHANGELOG.md
- grep -q -e '--shout' CHANGELOG.md && grep -q -e '--version' CHANGELOG.md && grep -q -e '--times' CHANGELOG.md

Make the change and keep it focused on the issue. Commit your work with a clear message. Do not push; that is done for you. Finish with a short summary of what you changed and why. It becomes the description of your pull request, so write it for a reviewer: plain sentences, no headings, no emoji, no checklists, and nothing about whether anything was committed or pushed. Say what you did not verify.