feat(integration): add partial update flags for existing installations

Add --update-hooks, --update-configs, and --update-deps flags to allow
targeted updates of specific components without full reinstallation.

Partial update modes:
- --update-hooks: Refresh only .husky directory with backup/restore
- --update-configs: Update config files (commitlint, validate-branch-name,
  PHP configs if applicable)
- --update-deps: Update npm and composer dependencies

Flags can be combined and used with existing flags like -J for JS/TS projects.
Includes documentation updates with usage examples.

Author: TerrorSquad

booster/integrate_booster.sh

@@ -1496,17 +1496,27 @@ function show_help() {
     echo "  -i          Show version information and exit"
     echo "  -h          Show this help message and exit"
     echo ""
+    echo "PARTIAL UPDATE OPTIONS (for existing installations):"
+    echo "  --update-hooks    Update only Git hooks (.husky directory)"
+    echo "  --update-configs  Update only config files (commitlint, validate-branch-name, etc.)"
+    echo "  --update-deps     Update only dependencies (composer/npm packages)"
+    echo ""
     echo "DESCRIPTION:"
     echo "  Integrates PHP Booster tooling into an existing PHP project."
     echo "  Supports both standard PHP projects and DDEV environments."
     echo "  Use -J flag for JavaScript/TypeScript projects without PHP."
     echo ""
+    echo "  For existing installations, use partial update flags to refresh"
+    echo "  specific components without a full reinstall."
+    echo ""
     echo "EXAMPLES:"
     echo "  $0              # Run integration with default settings"
     echo "  $0 -I           # Run in interactive mode (guided setup)"
     echo "  $0 -J           # Install hooks only (for JS/TS projects)"
     echo "  $0 -v           # Run with verbose output"
     echo "  $0 -i           # Show version information"
+    echo "  $0 --update-hooks    # Update Git hooks only"
+    echo "  $0 --update-configs  # Update config files only"
     echo ""
     echo "ENVIRONMENT VARIABLES:"
     echo "  BOOSTER_LOCAL_DEV=1     # Use local booster directory instead of GitHub"
@@ -1549,8 +1559,141 @@ function show_version_info_and_exit() {
 
 # --- Main Execution ---
 
+# Partial update mode flags
+UPDATE_HOOKS_ONLY=false
+UPDATE_CONFIGS_ONLY=false
+UPDATE_DEPS_ONLY=false
+
+# --- Partial Update Functions ---
+
+function update_hooks_only() {
+    log "Starting partial update: Git hooks only..."
+    
+    download_php_booster
+    
+    local husky_src="${BOOSTER_INTERNAL_PATH}/.husky"
+    if [ -d "$husky_src" ]; then
+        log "Updating .husky directory..."
+        
+        # Backup existing husky if it exists
+        if [ -d ".husky" ]; then
+            rm -rf ".husky.bak"
+            mv ".husky" ".husky.bak"
+            log "  Backed up existing .husky to .husky.bak"
+        fi
+        
+        mkdir -p .husky
+        
+        # Copy everything except the 'tests' directory
+        for item in "$husky_src"/*; do
+            local item_name=$(basename "$item")
+            if [ "$item_name" != "tests" ]; then
+                cp -R "$item" .husky/
+            fi
+        done
+        
+        # Set execute permissions for scripts and hooks
+        find ".husky" -type f \( -name "*.sh" -o -name "*.bash" -o -name "*.mjs" -o -name "pre-commit" -o -name "commit-msg" -o -name "pre-push" \) -exec chmod +x {} \;
+        
+        # Remove backup on success
+        rm -rf ".husky.bak"
+        
+        success "Git hooks updated successfully."
+    else
+        error "Could not find .husky directory in booster."
+    fi
+}
+
+function update_configs_only() {
+    log "Starting partial update: Config files only..."
+    
+    download_php_booster
+    
+    local updated_count=0
+    
+    # Config files to update (always overwrite)
+    local config_files=(
+        "commitlint.config.ts"
+        "validate-branch-name.config.cjs"
+        "renovate.json"
+    )
+    
+    for config in "${config_files[@]}"; do
+        local src="${BOOSTER_INTERNAL_PATH}/${config}"
+        if [ -f "$src" ]; then
+            cp "$src" . || warn "Failed to copy $config"
+            log "  Updated $config"
+            ((updated_count++))
+        else
+            log "  $config not found in booster, skipping."
+        fi
+    done
+    
+    # Update .editorconfig
+    local editorconfig_src="${BOOSTER_INTERNAL_PATH}/.editorconfig"
+    if [ -f "$editorconfig_src" ]; then
+        cp "$editorconfig_src" . || warn "Failed to copy .editorconfig"
+        log "  Updated .editorconfig"
+        ((updated_count++))
+    fi
+    
+    # PHP-specific configs (only if not hooks-only mode and files exist)
+    if [ "$HOOKS_ONLY_MODE" != true ] && [ -f "composer.json" ]; then
+        local php_configs=("ecs.php" "rector.php" "phpstan.neon.dist" "psalm.xml" "deptrac.yaml" "sonar-project.properties")
+        for config in "${php_configs[@]}"; do
+            local src="${BOOSTER_INTERNAL_PATH}/${config}"
+            if [ -f "$src" ]; then
+                cp "$src" . || warn "Failed to copy $config"
+                log "  Updated $config"
+                ((updated_count++))
+            fi
+        done
+    fi
+    
+    success "Config files updated ($updated_count files)."
+}
+
+function update_deps_only() {
+    log "Starting partial update: Dependencies only..."
+    
+    download_php_booster
+    
+    IS_DDEV_PROJECT=$(is_ddev_project)
+    
+    # Update node dependencies
+    log "Updating Node.js dependencies..."
+    install_node_dependencies
+    
+    # Update PHP dependencies (only if not hooks-only mode)
+    if [ "$HOOKS_ONLY_MODE" != true ] && [ -f "composer.json" ]; then
+        log "Updating PHP dependencies..."
+        add_code_quality_tools
+    fi
+    
+    success "Dependencies updated."
+}
 
 function main() {
+    # Parse long options first (before getopts)
+    local args=()
+    for arg in "$@"; do
+        case $arg in
+            --update-hooks)
+                UPDATE_HOOKS_ONLY=true
+                ;;
+            --update-configs)
+                UPDATE_CONFIGS_ONLY=true
+                ;;
+            --update-deps)
+                UPDATE_DEPS_ONLY=true
+                ;;
+            *)
+                args+=("$arg")
+                ;;
+        esac
+    done
+    set -- "${args[@]}"
+    
     # Process command line arguments
     while getopts ":vchiINJ" opt; do
         case $opt in
@@ -1567,6 +1710,42 @@ function main() {
     done
     shift $((OPTIND - 1))
 
+    # --- Handle Partial Update Modes ---
+    if [ "$UPDATE_HOOKS_ONLY" = true ] || [ "$UPDATE_CONFIGS_ONLY" = true ] || [ "$UPDATE_DEPS_ONLY" = true ]; then
+        log "Running in partial update mode..."
+        
+        # Check for existing booster installation
+        if [ ! -f ".booster-version" ] && [ ! -d ".husky" ]; then
+            warn "No existing booster installation detected. Running partial update anyway..."
+        fi
+        
+        check_dependencies
+        
+        if [ "$UPDATE_HOOKS_ONLY" = true ]; then
+            update_hooks_only
+        fi
+        
+        if [ "$UPDATE_CONFIGS_ONLY" = true ]; then
+            update_configs_only
+        fi
+        
+        if [ "$UPDATE_DEPS_ONLY" = true ]; then
+            update_deps_only
+        fi
+        
+        # Update version stamp with partial update info
+        local current_version
+        current_version=$(get_booster_version 2>/dev/null || echo "unknown")
+        if [ "$current_version" != "unknown" ]; then
+            create_version_stamp "$current_version" "partial-update"
+        fi
+        
+        success "Partial update completed."
+        exit 0
+    fi
+
+    # --- Full Installation Mode ---
+
     # Determine installation mode
     if [ "$HOOKS_ONLY_MODE" = true ]; then
         log "Starting php-booster integration (hooks-only mode for JS/TS projects)..."