ci(release): support prerelease tags in release workflow

Extend the release trigger to match tags with a prerelease suffix
(e.g. v0.2.1-rc.1). Detect the prerelease flag at runtime and pass
--prerelease to gh release create so GitHub marks the release correctly.

Author: geekmuse

.github/workflows/release.yml

@@ -4,6 +4,7 @@ on:
   push:
     tags:
       - 'v[0-9]+.[0-9]+.[0-9]+'
+      - 'v[0-9]+.[0-9]+.[0-9]+-*'
 
 jobs:
   release:
@@ -17,7 +18,15 @@ jobs:
 
       - name: Extract version from tag
         id: version
-        run: echo "version=${GITHUB_REF_NAME#v}" >> "$GITHUB_OUTPUT"
+        run: |
+          VERSION=${GITHUB_REF_NAME#v}
+          echo "version=$VERSION" >> "$GITHUB_OUTPUT"
+          # Mark as prerelease if version contains a hyphen (e.g. 0.3.0-rc.1)
+          if [[ "$VERSION" == *-* ]]; then
+            echo "prerelease=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "prerelease=false" >> "$GITHUB_OUTPUT"
+          fi
 
       # Build a distributable plugin ZIP.
       # Kanboard's plugin installer expects a ZIP containing a single root
@@ -43,7 +52,13 @@ jobs:
         env:
           GH_TOKEN: ${{ github.token }}
         run: |
+          PRERELEASE_FLAG=""
+          if [ "${{ steps.version.outputs.prerelease }}" = "true" ]; then
+            PRERELEASE_FLAG="--prerelease"
+          fi
+
           gh release create "${{ github.ref_name }}" \
             --title "${{ github.ref_name }}" \
             --generate-notes \
+            $PRERELEASE_FLAG \
             "$ARCHIVE"