feat: add Swift implementation of isspam (sisspam) with CI build and benchmark integration

- Add swift_isspam package with optimized main.swift using unsafe memory flags
- Extend CI workflow to install Swift 5.9.2 and include sisspam in build_all and benchmark
- Update Makefile with build_swift target and publish step for sisspam binary
- Add sisspam to .gitignore and README with author credit
- Enable Swift timing in bench.py alongside existing language implementations

.gitea/workflows/build.yaml

@@ -7,13 +7,19 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - run: apt update
-      - run: apt install build-essential valgrind make curl -y
+      - run: apt install build-essential valgrind make curl wget libcurl4-openssl-dev libxml2-dev binutils libc6-dev libgcc-s1 libstdc++6 zlib1g-dev -y
       - run: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- --default-toolchain nightly -y
+      - name: Install Swift
+        run: |
+          cd /opt
+          wget -q https://download.swift.org/swift-5.9.2-release/ubuntu2204/swift-5.9.2-RELEASE/swift-5.9.2-RELEASE-ubuntu22.04.tar.gz
+          tar xzf swift-5.9.2-RELEASE-ubuntu22.04.tar.gz
+          ln -s /opt/swift-5.9.2-RELEASE-ubuntu22.04/usr/bin/swift /usr/local/bin/swift
       - name: Check out repository code
         uses: actions/checkout@v4
       - name: List files in the repository
         run: |
           ls ${{ gitea.workspace }}
-      - run: export PATH=$HOME/.cargo/bin:$PATH && make build_all
-      - run: export PATH=$HOME/.cargo/bin:$PATH && make benchmark
+      - run: export PATH=$HOME/.cargo/bin:/opt/swift-5.9.2-RELEASE-ubuntu22.04/usr/bin:$PATH && make build_all
+      - run: export PATH=$HOME/.cargo/bin:/opt/swift-5.9.2-RELEASE-ubuntu22.04/usr/bin:$PATH && make benchmark
       - run: make publish