chore: set up release-please for automated releases (#24)

## Summary

- Adds `release-please` GitHub Action workflow that runs on pushes to
`main`
- Creates `release-please-config.json` with `simple` release type
(appropriate for a bash script project)
- Creates `.release-please-manifest.json` tracking the current version
(`0.9.1`)
- Adds `x-release-please-version` annotation to `src/crabcode` so the
`VERSION` variable is auto-updated on release

## How it works

1. When conventional commits (`feat:`, `fix:`, `chore:`, etc.) are
pushed to `main`, release-please automatically opens/updates a release
PR with version bump and changelog entries
2. Merging the release PR creates a GitHub release with the new tag
(`v0.x.x`)
3. The CHANGELOG.md is auto-formatted with Prettier after PR creation
4. The `VERSION` in `src/crabcode` is updated automatically via the
generic file updater

## Configuration choices

- **Release type**: `simple` — the right fit for a bash script project
(not node/python)
- **Tag format**: `v0.9.1` style (`include-v-in-tag: true`)
- **Pre-major bumping**: enabled (`bump-minor-pre-major` +
`bump-patch-for-minor-pre-major`) since we're pre-1.0
- **Bootstrap SHA**: set to current HEAD so release-please won't process
historical commits

## Test plan

- [ ] Merge this PR, then push a conventional commit (e.g. `feat: ...`)
to `main`
- [ ] Verify release-please opens a release PR with correct version bump
and changelog
- [ ] Merge the release PR and verify a GitHub release + tag is created
- [ ] Verify `src/crabcode` VERSION is updated in the release commit

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: mldangelo

.github/workflows/release-please.yml

@@ -0,0 +1,63 @@
+name: release-please
+run-name: crabcode release by @${{ github.actor }}
+
+concurrency:
+  group: release-please-${{ github.ref }}
+  cancel-in-progress: false
+
+on:
+  push:
+    branches:
+      - main
+  workflow_dispatch:
+
+jobs:
+  release-please:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: write
+      pull-requests: write
+    outputs:
+      release_created: ${{ steps.release.outputs.release_created }}
+      tag_name: ${{ steps.release.outputs.tag_name }}
+      version: ${{ steps.release.outputs.version }}
+    steps:
+      - uses: googleapis/release-please-action@v4
+        id: release
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Check if PR exists
+        id: check-pr
+        run: |
+          PR_OUTPUT='${{ steps.release.outputs.pr }}'
+          if [ -n "$PR_OUTPUT" ] && [ "$PR_OUTPUT" != "null" ]; then
+            echo "has_pr=true" >> $GITHUB_OUTPUT
+            echo "pr_branch=$(echo '${{ steps.release.outputs.pr }}' | jq -r '.headBranchName')" >> $GITHUB_OUTPUT
+          else
+            echo "has_pr=false" >> $GITHUB_OUTPUT
+          fi
+
+      - uses: actions/checkout@v6
+        if: steps.check-pr.outputs.has_pr == 'true'
+        with:
+          ref: ${{ steps.check-pr.outputs.pr_branch }}
+          fetch-depth: 1
+
+      - name: Format CHANGELOG.md with Prettier
+        if: steps.check-pr.outputs.has_pr == 'true'
+        run: |
+          echo "Formatting CHANGELOG.md on branch: ${{ steps.check-pr.outputs.pr_branch }}"
+          npx --yes prettier@latest --write CHANGELOG.md
+
+          if git diff --quiet CHANGELOG.md; then
+            echo "No formatting changes needed"
+          else
+            echo "Formatting changes detected, committing..."
+            git config user.name "github-actions[bot]"
+            git config user.email "github-actions[bot]@users.noreply.github.com"
+            git add CHANGELOG.md
+            git commit -m "chore: format CHANGELOG.md with prettier"
+            git push
+            echo "Formatting committed and pushed"
+          fi

.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "0.9.1"
+}

release-please-config.json

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "bootstrap-sha": "5496807d998f56cb2bed937c6707c72ef26932a0",
+  "include-component-in-tag": false,
+  "include-v-in-tag": true,
+  "packages": {
+    ".": {
+      "release-type": "simple",
+      "package-name": "crabcode",
+      "changelog-path": "CHANGELOG.md",
+      "bump-minor-pre-major": true,
+      "bump-patch-for-minor-pre-major": true,
+      "extra-files": [
+        {
+          "type": "generic",
+          "path": "src/crabcode",
+          "glob": false
+        }
+      ]
+    }
+  }
+}

src/crabcode

@@ -27,7 +27,7 @@
 
 set -e
 
-VERSION="0.9.1"
+VERSION="0.9.1" # x-release-please-version
 CONFIG_DIR="$HOME/.crabcode"
 CONFIG_FILE="$CONFIG_DIR/config.yaml"
 WIP_BASE="$CONFIG_DIR/wip"