Update action.yml to use specific Docker image and refactor entrypoint.sh for improved argument handling; add GitHub Actions workflow for building and publishing container image.

.github/workflows/publish-image.yml

@@ -0,0 +1,58 @@
+name: Build and Publish Container Image
+
+on:
+  push:
+    branches:
+      - main
+    tags:
+      - 'v*'
+  release:
+    types: [published]
+  workflow_dispatch: {}
+
+permissions:
+  contents: read
+  packages: write
+
+env:
+  REGISTRY: ghcr.io
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Derive image name (lowercase owner)
+        id: names
+        run: |
+          echo "OWNER_LC=${GITHUB_REPOSITORY_OWNER,,}" >> $GITHUB_ENV
+          echo "IMAGE=${REGISTRY}/${GITHUB_REPOSITORY_OWNER,,}/slinky" >> $GITHUB_ENV
+
+      - name: Log in to GHCR
+        uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Extract metadata (tags, labels)
+        id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.IMAGE }}
+          tags: |
+            type=ref,event=tag
+            type=raw,value=latest,enable={{is_default_branch}}
+            type=raw,value=v1
+
+      - name: Build and push
+        uses: docker/build-push-action@v6
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+
+