Added Shale, first commit

Author: NoryiE

.github/workflows/build-standalone.yml

@@ -0,0 +1,51 @@
+name: Build standalone
+
+on:
+  push:
+    paths:
+      - "src/**"
+      - "tools/build.lua"
+  workflow_dispatch:
+
+permissions:
+  contents: write
+
+concurrency:
+  group: build-standalone-${{ github.ref }}
+  cancel-in-progress: false
+
+jobs:
+  build:
+    name: Rebuild shale.lua
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Check out branch
+        uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
+          ref: ${{ github.ref_name }}
+
+      - name: Update to latest branch revision
+        run: git pull --ff-only origin "$GITHUB_REF_NAME"
+
+      - name: Install Lua 5.1
+        run: |
+          sudo apt-get update
+          sudo apt-get install --yes lua5.1
+
+      - name: Build standalone file
+        run: lua5.1 tools/build.lua
+
+      - name: Commit generated standalone file
+        run: |
+          if git diff --quiet -- shale.lua; then
+            echo "shale.lua is already up to date."
+            exit 0
+          fi
+
+          git config user.name "github-actions[bot]"
+          git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
+          git add shale.lua
+          git commit -m "chore: rebuild standalone shale.lua"
+          git push origin "HEAD:${GITHUB_REF_NAME}"