chore(release): build release notes from a changelog

.github/workflows/publish.yml

@@ -50,6 +50,23 @@ jobs:
             exit 1
           fi
 
+      # The release notes come from CHANGELOG.md, not from generated commit titles, so a
+      # missing entry is a missing release note. Fail here rather than after the upload.
+      - name: Extract the release notes
+        run: |
+          set -euo pipefail
+          awk -v ver="${{ inputs.version }}" '
+            $0 == "## " ver { found = 1; next }
+            found && /^## / { exit }
+            found { print }
+          ' CHANGELOG.md > release-notes.md
+          if [ ! -s release-notes.md ]; then
+            echo "::error::CHANGELOG.md has no '## ${{ inputs.version }}' section. Add one describing the contract change before publishing."
+            exit 1
+          fi
+          echo "Release notes for ${{ inputs.version }}:"
+          cat release-notes.md
+
       - name: Validate Gradle wrapper
         uses: gradle/actions/wrapper-validation@v4
 
@@ -122,7 +139,7 @@ jobs:
         run: |
           gh release create "${{ inputs.version }}" \
             --title "${{ inputs.version }}" \
-            --generate-notes
+            --notes-file release-notes.md
 
       - name: Summary
         run: |

.gitignore

@@ -6,3 +6,6 @@ local.properties
 
 # Pinned codegen toolchain, installed by scripts/install-swift-toolchain.sh.
 .tools/
+
+# Written by publish.yml when it extracts release notes from CHANGELOG.md
+release-notes.md

CHANGELOG.md

@@ -0,0 +1,18 @@
+# Changelog
+
+Contract changes from a consumer's point of view: what appeared, what changed shape, and what breaks
+if you upgrade. Field and enum renumbering matters more than its diff size suggests, so it gets
+called out explicitly even when nothing else did.
+
+`publish.yml` reads the section matching the version it is publishing and uses it as the GitHub
+release notes, so a version with no entry here does not release. Write the entry in the same PR that
+syncs the contract, while the diff is still in front of you.
+
+## 0.1.0
+
+First release. The Flipcash contract is now generated once here and published for both platforms,
+replacing the copies each app vendored and generated for itself.
+
+- Kotlin, on Maven Central as `com.flipcash:flipcash2-client-protocol`, under
+  `com.codeinc.flipcash.gen.*`.
+- Swift, as the `Flipcash2ClientProtocol` module. The git tag is the SPM release.