github actions: Create install bundle workflow

.github/workflows/bundle.yaml

@@ -1,4 +1,4 @@
-name: Bundle
+name: Bundle as μpkg package
 
 on:
   push:

.github/workflows/install-bundle.yaml

@@ -0,0 +1,32 @@
+name: Bundle as install package
+
+on:
+  push:
+    branches: ['*']
+    tags: ['!v*']
+  workflow_call: {}
+
+jobs:
+  install-bundle:
+    name: Create upkg-install.tar.gz
+    runs-on: ubuntu-latest
+    steps:
+    - name: Download μpkg bundle
+      uses: actions/download-artifact@v4
+      with:
+        name: upkg.tar.gz
+    - name: Create install package
+      run: |
+        checksum=$(shasum -a 256 upkg.tar.gz | cut -d ' ' -f1)
+        mkdir -p install/bin install/lib/upkg/.upkg/.packages install/lib/upkg/.upkg/.bin
+        tar -xzC install/lib/upkg/upkg.tar@$checksum -f upkg.tar.gz
+        ln -sT install/lib/upkg/.upkg/.packages/upkg.tar@$checksum install/lib/upkg/.upkg/upkg
+        ln -sT install/bin/upkg install/lib/upkg/.upkg/.bin/upkg
+    - name: Create upkg-install.tar.gz
+      run: tar -czC install -f upkg-install.tar.gz bin lib
+    - name: Upload upkg-install.tar.gz
+      uses: actions/upload-artifact@v4
+      with:
+        name: upkg-install.tar.gz
+        path: upkg-install.tar.gz
+        retention-days: 1

.github/workflows/release.yaml

@@ -6,7 +6,7 @@ on:
 
 jobs:
   create-release:
-    needs: [test, bundle]
+    needs: [test, install-bundle]
     runs-on: ubuntu-latest
     name: Create μpkg GitHub release
     environment: release
@@ -25,17 +25,21 @@ jobs:
         printf "message<<%s\n%s\n%s\n" "$eof" "$msg" "$eof" >> $GITHUB_OUTPUT
       env:
         REF: ${{ github.ref }}
-    - name: Download μpkg bundle
+    - name: Download μpkg package
       uses: actions/download-artifact@v4
       with:
         name: upkg.tar.gz
+    - name: Download μpkg install package
+      uses: actions/download-artifact@v4
+      with:
+        name: upkg-install.tar.gz
     - name: Create Release
       uses: ncipollo/release-action@v1
       with:
         name: ${{ steps.program_version.outputs.version }}
         body: ${{ steps.tag-message.outputs.message }}
         draft: false
         prerelease: false
-        artifacts: upkg.tar.gz
+        artifacts: upkg.tar.gz,upkg-install.tar.gz
         artifactErrorsFailBuild: true
         artifactContentType: application/gzip