fix(installer): resolve bash syntax error in read commands (#19)

Fixed bash syntax error caused by missing quotes around color variables
in command substitution within read -p commands.

Changes:
- Line 132: Added quotes around ${BLUE} and ${NC} in installation prompt
- Line 179: Added quotes around ${BLUE} and ${NC} in hooks prompt

This prevents "syntax error near unexpected token" errors during
installation on macOS and other systems.

Fixes #13

Credit: Original fix by @bartdorlandt in PR #14

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>
Co-authored-by: Bart Dorlandt <bartdorlandt@users.noreply.github.com>

install.sh

@@ -129,7 +129,7 @@ echo "  • Agent:    $AGENTS_DIR/claude-md-guardian.md"
 echo ""
 
 # Confirm installation
-read -p "$(echo -e ${BLUE}Proceed with installation? [Y/n]:${NC} )" confirm < /dev/tty
+read -p "$(echo -e "${BLUE}Proceed with installation? [Y/n]:${NC}")" confirm < /dev/tty
 confirm=${confirm:-Y}
 
 if [[ ! $confirm =~ ^[Yy]$ ]]; then
@@ -176,7 +176,7 @@ print_success "Agent installed → $AGENTS_DIR/claude-md-guardian.md"
 
 # Optional: Install quality hooks
 echo ""
-read -p "$(echo -e ${BLUE}Would you like to install quality hooks (pre-commit validation)? [y/N]:${NC} )" install_hooks < /dev/tty
+read -p "$(echo -e "${BLUE}Would you like to install quality hooks (pre-commit validation)? [y/N]:${NC}")" install_hooks < /dev/tty
 install_hooks=${install_hooks:-N}
 
 if [[ $install_hooks =~ ^[Yy]$ ]]; then