release v0.2.1

This release adds --help and --version flags, updates dependencies,
improves documentation for Windows support, and refines CI pipelines.

- Add --help and --version flags to main binary
- Update GitHub Actions workflow to latest major versions
- Update Go dependencies to latest versions
- Fix SPEC.md and README.md for current codebase (Windows fully supported)
- Update PLAN.md with roadmap for v0.3.0 and v1.0
- Add release command automation

.github/workflows/build.yml

@@ -75,6 +75,20 @@ jobs:
     needs: build
     runs-on: ubuntu-latest
     steps:
+      - uses: actions/checkout@v7
+        with:
+          fetch-depth: 0
+
+      - name: Extract release notes from commit message
+        id: release
+        run: |
+          MSG=$(git log -1 --pretty=format:"%B" "${{ github.sha }}")
+          {
+            echo 'body<<EOF'
+            echo "$MSG"
+            echo 'EOF'
+          } >> "$GITHUB_OUTPUT"
+
       - uses: actions/download-artifact@v8
         with:
           path: dist
@@ -83,5 +97,5 @@ jobs:
       - name: Create release and upload binaries
         uses: softprops/action-gh-release@v3
         with:
+          body: ${{ steps.release.outputs.body }}
           files: dist/*
-          generate_release_notes: true

.opencode/command/create-release.md

@@ -0,0 +1,35 @@
+---
+description: Create and push a release tag (e.g. /create-release 1.0.0)
+---
+
+Create a release tag and push it to origin. The GitHub Action will automatically build for all platforms and create the GitHub Release.
+
+## Steps
+
+1. Validate the version argument ($ARGUMENTS):
+   - Must be provided, otherwise show error and stop
+   - Must match semver format (e.g. 1.0.0, 0.9.1, 2.0.0-beta.1)
+
+2. Check for uncommitted changes:
+   - Run `git status --porcelain`
+   - If any output, warn the user and stop (commit first)
+
+3. Analyze changes since last release:
+   - Run `git log --oneline $(git describe --tags --abbrev=0 HEAD)..HEAD` to list all commits
+   - Read the changed files to understand context
+   - Write a concise, well-structured release summary in English with:
+     - A one-line overview
+     - Bullet points for each notable change (features, fixes, breaking changes)
+     - Keep it developer-friendly, no fluff
+
+4. Create release commit with the summary as message:
+   - Run `git commit --allow-empty -m "release v$ARGUMENTS\n\n<summary>"`
+   - The commit message IS the release notes — the GitHub Action picks it up automatically
+
+5. Create annotated tag on that commit:
+   - Run `git tag -a v$ARGUMENTS -m "Release v$ARGUMENTS"`
+
+6. Push commit and tag:
+   - Run `git push origin main --tags` (or current branch)
+
+7. Confirm success with the version number