Add Continuous Integration with Multiple Platforms

[mseminatore]

Issue: Add Continuous Integration with Multiple Platforms

Priority

🟡 Medium

Description

While GitHub Actions badge exists in README, it's unclear if CI is fully configured. Need comprehensive CI that:

• Tests on Windows, Linux, macOS
• Runs both debug and release builds
• Checks for memory leaks and undefined behavior
• Enforces code quality standards
• Reports test coverage

Proposed Implementation

1. Create .github/workflows/ci.yml:

   name: CI
   
   on: [push, pull_request]
   
   jobs:
     build:
       strategy:
         matrix:
           os: [ubuntu-latest, windows-latest, macos-latest]
           build_type: [Debug, Release]
       
       runs-on: ${{ matrix.os }}
       
       steps:
         - uses: actions/checkout@v4
           with:
             submodules: recursive
         
         - name: Configure CMake
           run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }}
         
         - name: Build
           run: cmake --build build
         
         - name: Test
           run: ctest --test-dir build --output-on-failure

2. Add sanitizer job (Linux only):

     sanitize:
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v4
           with:
             submodules: recursive
         
         - name: Configure with sanitizers
           run: |
             cmake -B build \
               -DCMAKE_BUILD_TYPE=Debug \
               -DCMAKE_C_FLAGS="-fsanitize=address,undefined -fno-omit-frame-pointer"
         
         - name: Build
           run: cmake --build build
         
         - name: Test
           run: ctest --test-dir build --output-on-failure

3. Add code coverage job:

     coverage:
       runs-on: ubuntu-latest
       steps:
         - uses: actions/checkout@v4
           with:
             submodules: recursive
         
         - name: Install lcov
           run: sudo apt-get install -y lcov
         
         - name: Configure
           run: cmake -B build -DCMAKE_BUILD_TYPE=Debug -DENABLE_COVERAGE=ON
         
         - name: Build and test
           run: |
             cmake --build build
             ctest --test-dir build
         
         - name: Generate coverage
           run: |
             lcov --capture --directory build --output-file coverage.info
             lcov --remove coverage.info '/usr/*' --output-file coverage.info
         
         - name: Upload to Codecov
           uses: codecov/codecov-action@v3

4. Add status badges to README.md:

   ![CI Status](https://github.com/USER/skeme/workflows/CI/badge.svg)
   ![Coverage](https://codecov.io/gh/USER/skeme/branch/main/graph/badge.svg)

Testing & Acceptance Criteria

• CI runs on push to main branch
• CI runs on all pull requests
• Tests pass on Ubuntu, Windows, macOS
• Both Debug and Release builds tested
• AddressSanitizer detects no memory errors
• UndefinedBehaviorSanitizer detects no UB
• Code coverage report generated and uploaded
• Build status badge shows in README
• Failed builds block PR merging
• CI completes in <5 minutes