Add pre-commit hook for automatic clang-format

Adds .githooks/pre-commit that automatically formats staged C++ files
before commit. This prevents formatting issues from reaching CI.

To enable: git config core.hooksPath .githooks

The hook:
- Finds clang-format (prefers versioned like clang-format-19)
- Formats only staged .cpp/.hpp/.h/.c files
- Re-stages formatted files automatically

Author: 0xeb

.githooks/README.md

@@ -0,0 +1,27 @@
+# Git Hooks
+
+This directory contains git hooks for the fastmcpp project.
+
+## Installation
+
+Run one of the following commands to enable the hooks:
+
+```bash
+# Option 1: Configure git to use this directory for hooks
+git config core.hooksPath .githooks
+
+# Option 2: Symlink (Linux/macOS)
+ln -sf ../../.githooks/pre-commit .git/hooks/pre-commit
+```
+
+## Available Hooks
+
+### pre-commit
+
+Automatically formats staged C++ files with clang-format before commit.
+
+- Finds clang-format (prefers versioned like clang-format-19)
+- Formats only staged `.cpp`, `.hpp`, `.h`, `.c` files
+- Re-stages formatted files automatically
+
+This ensures all committed code follows the project's formatting style.

.githooks/pre-commit

@@ -1,26 +1,34 @@
 #!/bin/bash
-# Pre-commit hook: auto-format staged C++ files
-#
-# Enable with: git config core.hooksPath .githooks
+# Pre-commit hook to automatically format C++ files with clang-format
+# Install: git config core.hooksPath .githooks
 
-STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep -E '\.(cpp|hpp)$')
+# Find clang-format (prefer versioned, fall back to unversioned)
+CLANG_FORMAT=""
+for cf in clang-format-19 clang-format-18 clang-format-17 clang-format; do
+    if command -v "$cf" &> /dev/null; then
+        CLANG_FORMAT="$cf"
+        break
+    fi
+done
 
-if [ -z "$STAGED_FILES" ]; then
+if [ -z "$CLANG_FORMAT" ]; then
+    echo "Warning: clang-format not found, skipping formatting"
     exit 0
 fi
 
-# Check if clang-format is available
-if ! command -v clang-format &> /dev/null; then
-    echo "Warning: clang-format not found, skipping auto-format"
+# Get staged C++ files
+STAGED_FILES=$(git diff --cached --name-only --diff-filter=ACM | grep -E '\.(cpp|hpp|h|c)$')
+
+if [ -z "$STAGED_FILES" ]; then
     exit 0
 fi
 
-# Auto-format and re-stage
+# Format each staged file
 for file in $STAGED_FILES; do
     if [ -f "$file" ]; then
-        clang-format -i "$file"
+        $CLANG_FORMAT -i "$file"
         git add "$file"
     fi
 done
 
-exit 0
+echo "Formatted $(echo "$STAGED_FILES" | wc -w) file(s) with $CLANG_FORMAT"