Add clang-format config, pre-commit hooks, and CI lint workflow

.clang-format

@@ -0,0 +1,2 @@
+BasedOnStyle: Google
+ColumnLimit: 100

.github/workflows/lint.yml

@@ -0,0 +1,49 @@
+name: Lint
+
+on:
+  pull_request:
+    branches: [main]
+    types: [opened, synchronize, reopened]
+
+concurrency:
+  group: lint-${{ github.event.pull_request.number }}
+  cancel-in-progress: true
+
+env:
+  FORCE_JAVASCRIPT_ACTIONS_TO_NODE24: true
+
+jobs:
+  lint:
+    name: "Lint"
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          fetch-depth: 0
+
+      - name: Check script permissions
+        run: |
+          errors=0
+          for f in scripts/*.sh; do
+            [ -f "$f" ] || continue
+            if [ ! -x "$f" ]; then
+              echo "::error file=$f::Script is not executable"
+              errors=$((errors + 1))
+            fi
+          done
+          if [ "$errors" -gt 0 ]; then
+            echo "::error::$errors script(s) missing executable permission"
+            exit 1
+          fi
+
+      - name: Build Docker image
+        run: docker build -f scripts/Dockerfile . --network host --tag cunls:local
+
+      - name: Run pre-commit (changed files)
+        run: |
+          docker run --rm \
+            -v "$(pwd):/cunls" \
+            -w /cunls \
+            cunls:local \
+            bash -c "git config --global --add safe.directory /cunls && pre-commit run --from-ref origin/main --to-ref HEAD"

.pre-commit-config.yaml

@@ -0,0 +1,13 @@
+repos:
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v5.0.0
+    hooks:
+      - id: trailing-whitespace
+      - id: end-of-file-fixer
+      - id: check-yaml
+
+  - repo: https://github.com/pre-commit/mirrors-clang-format
+    rev: v15.0.7
+    hooks:
+      - id: clang-format
+        types_or: [c++, cuda]

scripts/Dockerfile

@@ -21,7 +21,7 @@ RUN apt-get update && apt-get install -y --no-install-recommends \
 RUN python3 -m venv /opt/venv
 ENV PATH="/opt/venv/bin:$PATH"
 RUN pip install --upgrade pip && \
-    pip install scikit-build-core nanobind build wheel
+    pip install scikit-build-core nanobind build wheel pre-commit
 
 # Sphinx docs dependencies
 COPY docs/sphinx/requirements.txt /tmp/cunls-docs-requirements.txt