chore: add reusable workflows for Zola and docs-only repos

.github/workflows/docs-ci.yml

@@ -0,0 +1,32 @@
+# SPDX-FileCopyrightText: 2026 James Harton
+#
+# SPDX-License-Identifier: Apache-2.0
+
+name: Docs CI
+
+on:
+  workflow_call:
+
+permissions:
+  contents: read
+
+jobs:
+  reuse:
+    name: REUSE compliance
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: REUSE compliance check
+        uses: fsfe/reuse-action@772649cfa03a64a08c458c7cca9a6a473d74e7f9 # v6
+
+  canary:
+    name: canary
+    runs-on: ubuntu-latest
+    if: always()
+    needs:
+      - reuse
+    steps:
+      - name: Check all jobs passed
+        run: |
+          if [[ "${{ needs.reuse.result }}" != "success" ]]; then exit 1; fi
+          echo "All checks passed!"

.github/workflows/zola-ci.yml

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+# SPDX-FileCopyrightText: 2026 James Harton
+#
+# SPDX-License-Identifier: Apache-2.0
+
+name: Zola CI
+
+on:
+  workflow_call:
+    inputs:
+      enable-deploy:
+        description: 'Enable deployment to GitHub Pages'
+        required: false
+        type: boolean
+        default: false
+
+permissions:
+  contents: read
+
+jobs:
+  build:
+    name: zola build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        with:
+          submodules: 'recursive'
+      - run: sudo snap install --edge zola
+      - run: zola build
+      - uses: actions/upload-pages-artifact@7b1f4a764d45c48632c6b24a0339c27f5614fb0b # v4.0.0
+        with:
+          path: public/
+
+  reuse:
+    name: REUSE compliance
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+      - name: REUSE compliance check
+        uses: fsfe/reuse-action@772649cfa03a64a08c458c7cca9a6a473d74e7f9 # v6
+
+  canary:
+    name: canary
+    runs-on: ubuntu-latest
+    if: always()
+    needs:
+      - build
+      - reuse
+    steps:
+      - name: Check all jobs passed
+        run: |
+          if [[ "${{ needs.build.result }}" != "success" ]]; then exit 1; fi
+          if [[ "${{ needs.reuse.result }}" != "success" ]]; then exit 1; fi
+          echo "All checks passed!"
+
+  deploy:
+    name: deploy
+    runs-on: ubuntu-latest
+    needs: build
+    if: inputs.enable-deploy && github.ref == 'refs/heads/main'
+    permissions:
+      pages: write
+      id-token: write
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5