ci(cpp): introduce caching cmake and build + format optimization

.gitea/workflows/cpp.yml

@@ -17,8 +17,7 @@ jobs:
               run: |
                   find . \( -name '*.cpp' -o -name '*.h' -o -name '*.hpp' \) \
                     -not -path './build/*' \
-                    -exec clang-format -i --style=file {} +
-                  git diff --exit-code && echo "clang-format: passed"
+                    -exec clang-format --dry-run -Werror --style=file {} +
 
     build & lint:
         runs-on: alpine
@@ -30,11 +29,29 @@ jobs:
               with:
                   fetch-depth: 0
 
+            - name: Cache CMake build
+              uses: actions/cache@v4
+              with:
+                  path: build
+                  key: cpp-build-${{ hashFiles('CMakeLists.txt', '**/CMakeLists.txt') }}
+                  restore-keys: |
+                      cpp-build-
+
+            - name: Cache ccache
+              uses: actions/cache@v4
+              with:
+                  path: ~/.ccache
+                  key: ccache-${{ runner.os }}-${{ github.sha }}
+                  restore-keys: |
+                      ccache-${{ runner.os }}-
+
             - name: Configure
               run: cmake -B build -G Ninja -DENABLE_MODULES=plugin -DCMAKE_BUILD_TYPE=Release
 
             - name: Build
               run: ninja -C build
+              env:
+                  CMAKE_CXX_COMPILER_LAUNCHER: ccache
 
             - name: clang-tidy
               run: |