feat(ci): require changelog entry in PR checks, add patch/* branch policy

- New CI check: CHANGELOG.md must have entries under [Unreleased]
- Branch policy: patch/* can target dev or rc
- Branch policy: flat rc branch can target main

Authored-by: Moko Consulting
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.mokogitea/workflows/pr-check.yml

@@ -52,22 +52,22 @@ jobs:
                 REASON="Fix branches must target 'dev', not '${BASE}'"
               fi
               ;;
+            patch/*)
+              if [ "$BASE" != "dev" ] && [ "$BASE" != "rc" ]; then
+                ALLOWED=false
+                REASON="Patch branches must target 'dev' or 'rc', not '${BASE}'"
+              fi
+              ;;
             hotfix/*)
               if [ "$BASE" != "dev" ] && [ "$BASE" != "main" ]; then
                 ALLOWED=false
                 REASON="Hotfix branches can only target 'dev' or 'main', not '${BASE}'"
               fi
               ;;
-            alpha/*|beta/*)
-              if [ "$BASE" != "dev" ]; then
-                ALLOWED=false
-                REASON="Pre-release branches must target 'dev', not '${BASE}'"
-              fi
-              ;;
-            rc/*)
+            rc)
               if [ "$BASE" != "main" ]; then
                 ALLOWED=false
-                REASON="Release candidate branches must target 'main', not '${BASE}'"
+                REASON="RC branch can only merge into 'main', not '${BASE}'"
               fi
               ;;
             dev)
@@ -183,6 +183,28 @@ jobs:
               ;;
           esac
 
+      - name: Check changelog has unreleased entry
+        run: |
+          if [ ! -f "CHANGELOG.md" ]; then
+            echo "::warning::No CHANGELOG.md found"
+            exit 0
+          fi
+          # Check for content under [Unreleased] section
+          if ! grep -q "## \[Unreleased\]" CHANGELOG.md; then
+            echo "::error::CHANGELOG.md missing [Unreleased] section"
+            exit 1
+          fi
+          # Check there's at least one entry (Added/Changed/Fixed/Removed) under Unreleased
+          UNRELEASED_CONTENT=$(sed -n '/## \[Unreleased\]/,/## \[/p' CHANGELOG.md | grep -cE '^\s*-\s' || true)
+          if [ "$UNRELEASED_CONTENT" -eq 0 ]; then
+            echo "::error::CHANGELOG.md [Unreleased] section has no entries. Add a changelog entry describing your changes."
+            echo "## Changelog Check: Failed" >> $GITHUB_STEP_SUMMARY
+            echo "The \`[Unreleased]\` section in CHANGELOG.md has no entries." >> $GITHUB_STEP_SUMMARY
+            echo "Add a line like \`- Description of your change\` under a heading (\`### Added\`, \`### Changed\`, \`### Fixed\`, etc.)" >> $GITHUB_STEP_SUMMARY
+            exit 1
+          fi
+          echo "Changelog: ${UNRELEASED_CONTENT} entry/entries in [Unreleased]"
+
       - name: Verify package source
         run: |
           SOURCE_DIR="src"