Add clang-format, clang-tidy, and compiler CI matrix

.clang-format

@@ -0,0 +1,19 @@
+BasedOnStyle: LLVM
+IndentWidth: 4
+ColumnLimit: 100
+UseTab: Never
+BreakBeforeBraces: GNU
+AllowShortIfStatementsOnASingleLine: false
+AllowShortFunctionsOnASingleLine: Empty
+AllowShortBlocksOnASingleLine: Empty
+PointerAlignment: Left
+DerivePointerAlignment: false
+SpaceBeforeCpp11BracedList: true
+AlignConsecutiveAssignments: Consecutive
+AlignConsecutiveDeclarations: Consecutive
+AlignTrailingComments: true
+SpaceAfterCStyleCast: true
+SpaceBeforeParens: ControlStatements
+IncludeBlocks: Preserve
+# Keep include sorting enabled to ensure consistent formatter output across tooling.
+SortIncludes: true

.clang-tidy

@@ -0,0 +1,81 @@
+Checks: >
+  -*,
+  bugprone-*,
+  cert-*,
+  clang-analyzer-*,
+  concurrency-*,
+  misc-*,
+  performance-*,
+  portability-*,
+  readability-*,
+  -readability-magic-numbers,
+  -bugprone-easily-swappable-parameters
+WarningsAsErrors: '*'
+HeaderFilterRegex: '^(include|src|libgitledger)/.*\.(h|c)$'
+CheckOptions:
+  - key: readability-identifier-naming.TypedefCase
+    value: lower_case
+  - key: readability-identifier-naming.StructCase
+    value: lower_case
+  - key: readability-identifier-naming.UnionCase
+    value: lower_case
+  - key: readability-identifier-naming.EnumCase
+    value: lower_case
+  - key: readability-identifier-naming.EnumConstantCase
+    value: UPPER_CASE
+  - key: readability-identifier-naming.EnumConstantPrefix
+    value: 'GITLEDGER_'
+  - key: readability-identifier-naming.FunctionCase
+    value: lower_case
+  - key: readability-identifier-naming.FunctionPrefix
+    value: ''
+  - key: readability-identifier-naming.VariableCase
+    value: lower_case
+  - key: readability-identifier-naming.ParameterCase
+    value: lower_case
+  - key: readability-identifier-naming.MacroDefinitionCase
+    value: UPPER_CASE
+  - key: readability-identifier-naming.MacroDefinitionPrefix
+    value: 'GITLEDGER_'
+  - key: readability-identifier-naming.GlobalConstantCase
+    value: UPPER_CASE
+  - key: readability-identifier-naming.GlobalConstantPrefix
+    value: 'GITLEDGER_'
+  - key: readability-function-cognitive-complexity.Threshold
+    value: '25'
+  - key: readability-function-size.LineThreshold
+    value: '50'
+  - key: readability-function-size.StatementThreshold
+    value: '60'
+  - key: readability-function-size.BranchThreshold
+    value: '15'
+  - key: readability-function-size.ParameterThreshold
+    value: '8'
+  - key: readability-function-size.NestingThreshold
+    value: '5'
+  - key: readability-function-size.CallThreshold
+    value: '30'
+  - key: bugprone-suspicious-string-compare.WarnOnImplicitComparison
+    value: 'true'
+  - key: bugprone-suspicious-string-compare.WarnOnLogicalNotComparison
+    value: 'true'
+  - key: cert-err33-c.CheckedFunctions
+    # Mirror the cert-err33-c default allowlist so we can trim entries locally in future diffs.
+    value: |
+      ::aligned_alloc;::calloc;::clock;::fclose;::ferror;::fflush;::fgetc;::fgetpos;::fgets;::fgetwc;::fopen;
+      ::fprintf;::fputc;::fputs;::fputwc;::fread;::freopen;::fscanf;::fseek;::fsetpos;::ftell;::fwprintf;
+      ::fwrite;::fwscanf;::getc;::getchar;::gets;::getwc;::getwchar;::gmtime;::localtime;::malloc;::mbrtowc;
+      ::mbsrtowcs;::mbstowcs;::memchr;::mktime;::printf;::putc;::putchar;::puts;::putwc;::putwchar;::raise;
+      ::realloc;::remove;::rename;::scanf;::setlocale;::setvbuf;::signal;::snprintf;::sprintf;::sscanf;::strchr;
+      ::strerror_s;::strftime;::strpbrk;::strrchr;::strstr;::strtod;::strtof;::strtoimax;::strtok;::strtol;
+      ::strtoll;::strtoul;::strtoull;::strtoumax;::strxfrm;::swprintf;::swscanf;::time;::tmpfile;::tmpnam;
+      ::ungetc;::ungetwc;::vfprintf;::vfscanf;::vfwprintf;::vfwscanf;::vprintf;::vscanf;::vsnprintf;::vsprintf;
+      ::vsscanf;::vswprintf;::vswscanf;::vwprintf;::vwscanf;::wcrtomb;::wcschr;::wcsftime;::wcspbrk;::wcsrchr;
+      ::wcsrtombs;::wcsstr;::wcstod;::wcstof;::wcstoimax;::wcstok;::wcstol;::wcstoll;::wcstombs;::wcstoul;
+      ::wcstoull;::wcstoumax;::wcsxfrm;::wctob;::wmemchr;::wprintf;::wscanf
+  - key: performance-move-const-arg.CheckTriviallyCopyableMove
+    value: 'false'
+  - key: performance-no-automatic-move.AllowedTypes
+    value: ''
+  - key: misc-misplaced-const.CheckPrimitiveCasts
+    value: 'true'

.editorconfig

@@ -0,0 +1,39 @@
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.{c,h}]
+indent_style = space
+indent_size = 4
+
+[*.{yml,yaml,json,md,txt}]
+indent_style = space
+indent_size = 2
+
+[*.md]
+trim_trailing_whitespace = false
+
+[Makefile]
+indent_style = tab
+indent_size = tab
+tab_width = 4
+
+[*.sh]
+indent_style = space
+indent_size = 2
+
+[CMakeLists.txt]
+indent_style = space
+indent_size = 2
+
+[*.cmake]
+indent_style = space
+indent_size = 2
+
+[meson.build]
+indent_style = space
+indent_size = 2

.github/workflows/ci.yml

@@ -0,0 +1,126 @@
+name: CI
+
+on:
+  push:
+    branches: [main, feat/coding-standards]
+  pull_request:
+    branches: [main]
+
+jobs:
+  linux-matrix:
+    name: ${{ matrix.name }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - name: GCC 14 (Ubuntu 24.04)
+            os: ubuntu-24.04
+            cc: gcc-14
+            cxx: g++-14
+            packages: gcc-14 g++-14 clang-format-18 clang-tidy-18
+            clang_format: clang-format-18
+            clang_tidy: clang-tidy-18
+            run_tidy: true
+          - name: Clang 18 (Ubuntu 24.04)
+            os: ubuntu-24.04
+            cc: clang-18
+            cxx: clang++-18
+            packages: clang-18 clang++-18 clang-format-18 clang-tidy-18
+            clang_format: clang-format-18
+            clang_tidy: clang-tidy-18
+            run_tidy: false
+    env:
+      CC: ${{ matrix.cc }}
+      CXX: ${{ matrix.cxx }}
+      CLANG_FORMAT: ${{ matrix.clang_format }}
+      CLANG_TIDY: ${{ matrix.clang_tidy }}
+      LIBGITLEDGER_CONTAINER_IMAGE: libgitledger-ci:latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          sudo apt-get update
+          sudo apt-get install -y build-essential ninja-build cmake python3-pip rsync ${{ matrix.packages }}
+          python3 -m pip install --upgrade pip
+          python3 -m pip install meson
+
+      - name: Display toolchain versions
+        run: |
+          ${CC} --version
+          ${CXX} --version
+          ${CLANG_FORMAT} --version
+          ${CLANG_TIDY} --version
+          cmake --version
+          meson --version
+
+      - name: Verify Docker availability
+        run: docker version
+
+      - name: Pre-build CI container image
+        run: docker build -t libgitledger-ci:latest -f tools/container/Dockerfile .
+
+      - name: Verify make targets exist
+        # The container dispatch script expects these orchestrated targets; a dry run proves they resolve.
+        run: |
+          for target in cmake test-cmake meson test-meson format-check tidy; do
+            make -n "$target" >/dev/null
+          done
+
+      - name: Build with CMake
+        run: make cmake
+
+      - name: Run CMake tests
+        run: make test-cmake
+
+      - name: Build with Meson
+        run: make meson
+
+      - name: Run Meson tests
+        run: make test-meson
+
+      - name: clang-format check
+        run: make format-check
+
+      - name: clang-tidy check
+        if: ${{ matrix.run_tidy }}
+        # tools/lint/run_clang_tidy.sh filters compile_commands.json to exclude test TU entries
+        run: make tidy
+
+      - name: Validate activity log schema
+        run: make activity-validate
+
+  windows-msvc:
+    name: MSVC (Windows)
+    runs-on: windows-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install dependencies
+        run: |
+          python -m pip install --upgrade pip
+          python -m pip install meson ninja
+          choco install ninja -y
+        shell: pwsh
+
+      - name: Configure CMake (Ninja)
+        run: cmake -S . -B build-msvc -G "Ninja" -DCMAKE_BUILD_TYPE=Release -DCMAKE_C_STANDARD=17 -DCMAKE_C_STANDARD_REQUIRED=ON
+        shell: pwsh
+
+      - name: Build
+        run: cmake --build build-msvc
+        shell: pwsh
+
+      - name: Run CTest
+        run: ctest --test-dir build-msvc --output-on-failure
+        shell: pwsh
+
+      - name: Configure Meson
+        run: |
+          meson setup meson-msvc --buildtype release
+          meson compile -C meson-msvc
+          meson test -C meson-msvc --print-errorlogs
+        shell: pwsh

.gitignore

@@ -20,6 +20,7 @@ Icon
 build/
 build-debug/
 build-release/
+build-tidy/
 meson-debug/
 meson-release/
 meson-*/

.markdownlint.yaml

@@ -0,0 +1,9 @@
+MD013:
+  line_length: 240
+  code_blocks: false
+  tables: false
+MD041: true
+MD024:
+  siblings_only: true
+MD029:
+  style: ordered