Add basic Gitea Actions CI workflow

Run pre-commit checks and build/test the project on clang and gcc for
both amd64 and arm64. weaseljson is built and installed locally because
weaseldb depends on it via find_package.

.gitea/workflows/ci.yml

@@ -0,0 +1,69 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  pre-commit:
+    runs-on: ubuntu-latest-amd64
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Install pre-commit
+        run: pipx install pre-commit
+
+      - name: Run pre-commit
+        run: ~/.local/bin/pre-commit run --all-files --show-diff-on-failure
+
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: clang-amd64
+            runner: ubuntu-latest-amd64
+            cmake_args: -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
+          - name: clang-arm64
+            runner: ubuntu-latest-arm64
+            cmake_args: -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
+          - name: gcc-amd64
+            runner: ubuntu-latest-amd64
+            cmake_args: -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++
+          - name: gcc-arm64
+            runner: ubuntu-latest-arm64
+            cmake_args: -DCMAKE_C_COMPILER=gcc -DCMAKE_CXX_COMPILER=g++
+    runs-on: ${{ matrix.runner }}
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          path: weaseldb
+
+      - name: Checkout weaseljson
+        uses: actions/checkout@v4
+        with:
+          repository: weaselab/weaseljson
+          path: weaseljson
+
+      - name: Install deps
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y build-essential clang cmake
+
+      - name: Build and install weaseljson
+        run: |
+          cmake -S weaseljson -B weaseljson/build \
+            -DCMAKE_BUILD_TYPE=Release \
+            -DCMAKE_INSTALL_PREFIX="$(pwd)/weaseljson/install"
+          cmake --build weaseljson/build -j "$(nproc)"
+          cmake --install weaseljson/build
+
+      - name: Build weaseldb
+        run: |
+          cmake -S weaseldb -B weaseldb/build ${{ matrix.cmake_args }} \
+            -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
+            -DCMAKE_PREFIX_PATH="$(pwd)/weaseljson/install"
+          cmake --build weaseldb/build -j "$(nproc)"
+
+      - name: Test
+        run: |
+          cd weaseldb/build
+          ctest --output-on-failure -j "$(nproc)" --timeout 90