ci(lint-md): add rumdl alongside markdownlint

.github/workflows/lint-md.yml

@@ -24,3 +24,45 @@ jobs:
           reporter: github-pr-review
           level: info
           fail_level: any
+  lint-md-rumdl:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: write
+    steps:
+      - name: Checkout code
+        # yamllint disable-line rule:line-length
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        with:
+          persist-credentials: false
+      - name: Set up uv
+        # yamllint disable-line rule:line-length
+        uses: astral-sh/setup-uv@37802adc94f370d6bfd71619e3f0bf239e1f3b78  # v7.6.0
+        with:
+          enable-cache: false
+      - name: Set up reviewdog
+        # yamllint disable-line rule:line-length
+        uses: reviewdog/action-setup@d8a7baabd7f3e8544ee4dbde3ee41d0011c3a93f  # ratchet:reviewdog/action-setup@v1
+      - name: Lint Markdown files with rumdl via reviewdog
+        env:
+          REVIEWDOG_GITHUB_API_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |-
+          uvx rumdl check . --output-format json-lines > rumdl.jsonl || true
+          jq -c '
+            {
+              source: {name: "rumdl"},
+              severity: (.severity | ascii_upcase),
+              message: .message,
+              location: {
+                path: .file,
+                range: {start: {line: .line, column: .column}}
+              },
+              code: {value: .rule}
+            }
+          ' rumdl.jsonl \
+            | reviewdog \
+                -f=rdjsonl \
+                -name=rumdl \
+                -reporter=github-pr-review \
+                -filter-mode=added \
+                -fail-level=any