feat: Add cocogitto conventional commits check

[berkus]

Check PR commits are compliant, so we can generate changelogs automagically.

[Copilot]

Pull request overview

Adds a Cocogitto-based conventional commit check to pull requests so commit messages can be validated consistently and used for changelog generation.

Changes:

• Add a cog.toml Cocogitto configuration (tag prefix, merge-commit ignore, custom commit types).
• Add a GitHub Actions workflow to run cog check against PR commits.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
cog.toml	Introduces Cocogitto configuration used by CI to validate/interpret commit messages.
.github/workflows/cog.yaml	Adds a PR workflow that checks commit message compliance via cocogitto-action.

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[Copilot]

actions/checkout is pinned to the PR head SHA, but the cog check range references ${{ github.event.pull_request.base.sha }} as well. If the PR branch is behind the base branch, that base SHA may not exist in the checked-out repository, causing cog/git to fail resolving the range. Consider explicitly fetching the base ref/SHA (or computing the merge-base between base and head) before running the check so the revision range is always available.

[Copilot]

This workflow uses ${{github.*}} expressions without the spacing used elsewhere in this repo (e.g., ${{ github.* }} in .github/workflows/ci.yaml) and pins actions/checkout to v6.0.2 while other workflows use actions/checkout@v6. Aligning these improves consistency and avoids relying on a potentially non-existent patch tag.

Suggested change

	uses: actions/checkout@v6.0.2
	with:
	fetch-tags: true
	fetch-depth: 0
	# pick the pr HEAD instead of the merge commit
	ref: ${{github.event.pull_request.head.sha}}
	- name: Conventional commit check
	uses: cocogitto/cocogitto-action@v4.1.0
	with:
	command: check
	args: ${{github.event.pull_request.base.sha}}..${{github.event.pull_request.head.sha}}
	uses: actions/checkout@v6
	with:
	fetch-tags: true
	fetch-depth: 0
	# pick the pr HEAD instead of the merge commit
	ref: ${{ github.event.pull_request.head.sha }}
	- name: Conventional commit check
	uses: cocogitto/cocogitto-action@v4.1.0
	with:
	command: check
	args: ${{ github.event.pull_request.base.sha }}..${{ github.event.pull_request.head.sha }}