ci: bump actions + dynamic go version + auto-release + badge fix (#14) #4

	name: release

	# Auto-cuts a beta prerelease on every main push.
	# Tag pushes are ignored so the workflow doesn't recurse.
	on:
	push:
	branches: [main]

	permissions:
	contents: write

	concurrency:
	group: release-main
	cancel-in-progress: false

	jobs:
	release:
	name: auto-tag + release
	runs-on: ubuntu-latest
	steps:
	- uses: actions/checkout@v6
	with:
	fetch-depth: 0

	- name: Compute next beta tag
	id: ver
	run: \|
	latest=$(git tag -l 'v0.0.0-beta.*' \
	\| grep -E 'v0\.0\.0-beta\.[0-9]+$' \
	\| sort -V \
	\| tail -1)
	if [ -z "$latest" ]; then
	next="v0.0.0-beta.1"
	else
	n=${latest##*.}
	next="v0.0.0-beta.$((n+1))"
	fi
	echo "tag=$next" >> "$GITHUB_OUTPUT"
	echo "Next tag: $next"

	- name: Create tag + release
	env:
	GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
	run: \|
	set -eu
	tag="${{ steps.ver.outputs.tag }}"
	git tag "$tag"
	git push origin "$tag"
	gh release create "$tag" \
	--target "${{ github.sha }}" \
	--prerelease \
	--generate-notes \
	--title "$tag"

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