ci: add docs build check on pull requests (#35)

Author: zurfjereluhmie

.github/workflows/ci.yml

@@ -70,9 +70,48 @@ jobs:
     needs:
       - lint
       - test
+      - docs-check
     runs-on: ubuntu-latest
     steps:
       - name: Decide whether the needed jobs succeeded or failed
         uses: re-actors/alls-green@release/v1
         with:
+          allowed-skips: docs-check
           jobs: ${{ toJSON(needs) }}
+
+  docs-check:
+    name: Docs build check
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v6
+
+      - uses: dorny/paths-filter@v4
+        id: filter
+        with:
+          filters: |
+            docs:
+              - docs/**
+              - mkdocs.yml
+              - src/**
+              - .github/workflows/docs.yml
+
+      - name: Install uv
+        if: steps.filter.outputs.docs == 'true'
+        uses: astral-sh/setup-uv@v8.0.0
+        with:
+          enable-cache: true
+
+      - name: Set up Python
+        if: steps.filter.outputs.docs == 'true'
+        uses: actions/setup-python@v6
+        with:
+          python-version-file: .python-version
+
+      - name: Install dependencies
+        if: steps.filter.outputs.docs == 'true'
+        run: uv sync --group dev
+
+      - name: Build docs (dry run)
+        if: steps.filter.outputs.docs == 'true'
+        run: uv run mkdocs build --clean --strict