ci: add action to build devcontainer image

.github/workflows/psc-cuda-devcontainer.yml

@@ -5,6 +5,13 @@ on:
     branches: [ main, 'pr/*' ]
   pull_request:
     branches: [ main ]
+  workflow_dispatch:
+    inputs:
+      push_image:
+        description: Build and push the devcontainer image to GHCR
+        required: true
+        type: boolean
+        default: true
 
 permissions:
   contents: read
@@ -13,6 +20,7 @@ permissions:
 jobs:
   build-cuda-devcontainer:
     runs-on: ubuntu-latest
+    if: github.event_name != 'workflow_dispatch'
 
     steps:
       - name: Checkout (github)
@@ -35,3 +43,26 @@ jobs:
           runCmd: |
             cmake -S . -B build-cuda-ci -DCMAKE_BUILD_TYPE=RelWithDebInfo -DPSC_GPU=cuda -DGTENSOR_DEVICE=cuda -G Ninja
             cmake --build build-cuda-ci
+
+  push-cuda-devcontainer:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'workflow_dispatch' && inputs.push_image
+
+    steps:
+      - name: Checkout (github)
+        uses: actions/checkout@v4
+
+      - name: Login to GitHub Container Registry
+        uses: docker/login-action@v2
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Build and push devcontainer image
+        uses: devcontainers/ci@v0.3
+        with:
+          configFile: .devcontainer/devcontainer.json
+          imageName: ghcr.io/psc-code/psc-devcontainer
+          cacheFrom: ghcr.io/psc-code/psc-devcontainer
+          push: always