fix: embed changelog excerpt in release notes

Adds release-notes.sh, extracting the matching CHANGELOG.md section
(Keep a Changelog format) for GitHub release notes. release.yml pulls
the exact tagged version (falling back to the newest entry for a
non-tag workflow_dispatch); unstable.yml always uses the newest entry,
since its build version never matches a changelog heading exactly.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Author: malys

.github/workflows/release.yml

@@ -66,6 +66,15 @@ jobs:
           name: mg4-abrp-telemetry-stable
           path: dist/*.apk
 
+      - name: Extract changelog
+        id: changelog
+        run: |
+          {
+            echo 'notes<<CHANGELOG_EOF'
+            ./release-notes.sh "${{ github.ref_name }}" || ./release-notes.sh --latest
+            echo 'CHANGELOG_EOF'
+          } >> "$GITHUB_OUTPUT"
+
       - name: Publish GitHub Release
         uses: softprops/action-gh-release@v2
         with:
@@ -85,3 +94,6 @@ jobs:
             ### Install
             Copy the APK to a USB stick, open the Files app on the car and tap it.
             See the README for how to reach the Files app on an MG4.
+
+            ### Changelog
+            ${{ steps.changelog.outputs.notes }}

.github/workflows/unstable.yml

@@ -71,6 +71,15 @@ jobs:
         id: date
         run: echo "value=$(date -u +'%Y-%m-%d %H:%M UTC')" >> "$GITHUB_OUTPUT"
 
+      - name: Extract changelog
+        id: changelog
+        run: |
+          {
+            echo 'notes<<CHANGELOG_EOF'
+            ./release-notes.sh --latest
+            echo 'CHANGELOG_EOF'
+          } >> "$GITHUB_OUTPUT"
+
       # One rolling pre-release: drop the previous release and its tag so the new one is
       # published at this commit instead of leaving the tag behind on the old sha.
       - name: Reset rolling unstable release
@@ -98,4 +107,7 @@ jobs:
             an APK only over https from a GitHub host, and only if it is signed with the
             same certificate as the running app — otherwise it deletes the file.
 
+            ### Changelog
+            ${{ steps.changelog.outputs.notes }}
+
             Commit: ${{ github.sha }}

release-notes.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+# Extracts one version's section from CHANGELOG.md (Keep a Changelog format) for use
+# as GitHub release notes.
+#
+# Usage:
+#   release-notes.sh <version>   Section for "## [<version>]" — exact match, leading "v" stripped
+#   release-notes.sh --latest    Section for the newest "## [" entry — used by the unstable
+#                                 channel, whose build version never matches a heading exactly
+set -euo pipefail
+
+changelog="${CHANGELOG_FILE:-CHANGELOG.md}"
+[ -f "$changelog" ] || { echo "::error::$changelog not found" >&2; exit 1; }
+
+mode="${1:?usage: release-notes.sh <version>|--latest}"
+if [ "$mode" = "--latest" ]; then
+  want_latest=1
+  version=""
+else
+  want_latest=0
+  version="${mode#v}"
+fi
+
+section=$(awk -v ver="$version" -v want_latest="$want_latest" '
+  /^## \[/ {
+    if (found) exit
+    if (want_latest == "1") { found = 1; next }
+    prefix = "## [" ver "]"
+    if (substr($0, 1, length(prefix)) == prefix) found = 1
+    next
+  }
+  found { print }
+' "$changelog")
+
+# Trim leading/trailing blank lines.
+section=$(printf '%s\n' "$section" | sed -e '/./,$!d' -e ':a' -e '/^\n*$/{$d;N;ba' -e '}')
+
+if [ -z "$section" ]; then
+  echo "::error::No changelog section found for '$mode' in $changelog" >&2
+  exit 1
+fi
+
+printf '%s\n' "$section"