ci: build the documentation

Author: azmeuk

.github/workflows/tests.yaml

@@ -28,3 +28,16 @@ jobs:
           enable-cache: true
       - name: Run style checks
         run: uv run prek run --all-files --show-diff-on-failure
+
+  doc:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+      - name: Install uv
+        uses: astral-sh/setup-uv@c18668ad3cf93ea998bef934396af7bb5c839dc7 # v10.2.0
+        with:
+          version: "0.12.13"
+          enable-cache: true
+      - name: Install dependencies
+        run: uv sync --group doc
+      - run: uv run sphinx-build -W --keep-going -b html doc build/sphinx/html