ci: build and check every template with texforge on each pull request

.github/workflows/check-templates.yml

@@ -0,0 +1,49 @@
+name: check-templates
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+concurrency:
+  group: check-templates-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  check:
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    env:
+      TEXFORGE_VERSION: v0.10.1
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+
+      - name: Install texforge
+        run: |
+          set -euo pipefail
+          base="https://github.com/UniverLab/texforge/releases/download/${TEXFORGE_VERSION}"
+          asset="texforge-${TEXFORGE_VERSION}-x86_64-unknown-linux-musl.tar.gz"
+          cd "$RUNNER_TEMP"
+          curl -fsSLO "$base/$asset"
+          curl -fsSLO "$base/SHA256SUMS.txt"
+          grep " $asset\$" SHA256SUMS.txt | sha256sum -c -
+          mkdir -p texforge-bin
+          tar -xzf "$asset" -C texforge-bin
+          bin=$(find texforge-bin -type f -name texforge | head -1)
+          install -m 0755 "$bin" /usr/local/bin/texforge
+          texforge --version
+
+      - name: Cache the TeX engine and bundle
+        uses: actions/cache@v4
+        with:
+          path: |
+            ~/.texforge
+            ~/.cache/Tectonic
+          key: texforge-${{ env.TEXFORGE_VERSION }}-${{ runner.os }}
+
+      - name: Check every template
+        run: bash ./check-templates.sh