feat: implement markitect installer with version/release commands (issue #80)

- Add comprehensive version information system with git integration
- Add `markitect version` and `markitect release` commands with multiple output formats
- Add global `--version` flag for quick version checking
- Create Python installer script with advanced options (install.py)
- Create shell installer wrapper for easy installation (install.sh)
- Add comprehensive installation documentation (INSTALL.md)
- Support user and system-wide installations with virtual environments
- Include development mode installation with test dependencies
- Add installation status checking and uninstall functionality

Commands added:
- `markitect --version` - Quick version display
- `markitect version [--short]` - Detailed version information
- `markitect release [--format text|json|yaml]` - Release information

Installer features:
- Automatic virtual environment creation
- Symbolic link management for global access
- Custom installation paths and prefixes
- Development mode with test dependencies
- Installation validation and troubleshooting

Resolves #80

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

Co-Authored-By: Claude <noreply@anthropic.com>

install.sh

@@ -0,0 +1,160 @@
+#!/bin/bash
+#
+# MarkiTect Quick Installer
+#
+# This script provides a simple way to install MarkiTect.
+# It's a wrapper around the Python installer script.
+#
+# Usage:
+#   ./install.sh [options]
+#   curl -sSL https://raw.githubusercontent.com/example/markitect/main/install.sh | bash
+#
+# Options:
+#   --system          Install system-wide (requires sudo)
+#   --dev             Install in development mode
+#   --check           Check installation status
+#   --uninstall       Uninstall MarkiTect
+#   --help            Show help
+
+set -e
+
+# Default options
+SYSTEM=""
+DEV=""
+CHECK=""
+UNINSTALL=""
+HELP=""
+
+# Colors for output
+RED='\033[0;31m'
+GREEN='\033[0;32m'
+YELLOW='\033[1;33m'
+BLUE='\033[0;34m'
+NC='\033[0m' # No Color
+
+# Function to print colored output
+print_info() {
+    echo -e "${BLUE}ℹ️  $1${NC}"
+}
+
+print_success() {
+    echo -e "${GREEN}✅ $1${NC}"
+}
+
+print_warning() {
+    echo -e "${YELLOW}⚠️  $1${NC}"
+}
+
+print_error() {
+    echo -e "${RED}❌ $1${NC}"
+}
+
+# Parse command line arguments
+while [[ $# -gt 0 ]]; do
+    case $1 in
+        --system)
+            SYSTEM="--system"
+            shift
+            ;;
+        --dev)
+            DEV="--dev"
+            shift
+            ;;
+        --check)
+            CHECK="--check"
+            shift
+            ;;
+        --uninstall)
+            UNINSTALL="--uninstall"
+            shift
+            ;;
+        --help|-h)
+            HELP="--help"
+            shift
+            ;;
+        *)
+            print_error "Unknown option: $1"
+            exit 1
+            ;;
+    esac
+done
+
+# Show help if requested
+if [[ -n "$HELP" ]]; then
+    cat << EOF
+MarkiTect Quick Installer
+
+Usage: $0 [options]
+
+Options:
+  --system      Install system-wide (requires sudo)
+  --dev         Install in development mode with test dependencies
+  --check       Check current installation status
+  --uninstall   Uninstall MarkiTect
+  --help        Show this help message
+
+Examples:
+  $0                    # Install for current user
+  $0 --system          # Install system-wide
+  $0 --dev             # Install in development mode
+  $0 --check           # Check installation status
+  $0 --uninstall       # Uninstall MarkiTect
+
+For more advanced options, use the Python installer directly:
+  python install.py --help
+EOF
+    exit 0
+fi
+
+# Check if Python is available
+if ! command -v python3 &> /dev/null; then
+    print_error "Python 3 is required but not found"
+    print_info "Please install Python 3.8 or higher and try again"
+    exit 1
+fi
+
+# Check Python version
+python_version=$(python3 -c "import sys; print(f'{sys.version_info.major}.{sys.version_info.minor}')")
+required_version="3.8"
+
+if ! python3 -c "import sys; sys.exit(0 if sys.version_info >= (3, 8) else 1)"; then
+    print_error "Python $required_version or higher is required (found: $python_version)"
+    exit 1
+fi
+
+print_success "Python $python_version found"
+
+# Determine script directory
+SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+INSTALLER_SCRIPT="$SCRIPT_DIR/install.py"
+
+# Check if installer script exists
+if [[ ! -f "$INSTALLER_SCRIPT" ]]; then
+    print_error "Installer script not found: $INSTALLER_SCRIPT"
+    print_info "Make sure you're running this from the MarkiTect project directory"
+    exit 1
+fi
+
+# Build command
+cmd="python3 $INSTALLER_SCRIPT"
+
+if [[ -n "$SYSTEM" ]]; then
+    cmd="$cmd $SYSTEM"
+    print_warning "System installation requires sudo privileges"
+fi
+
+if [[ -n "$DEV" ]]; then
+    cmd="$cmd $DEV"
+fi
+
+if [[ -n "$CHECK" ]]; then
+    cmd="$cmd $CHECK"
+fi
+
+if [[ -n "$UNINSTALL" ]]; then
+    cmd="$cmd $UNINSTALL"
+fi
+
+# Run the installer
+print_info "Running: $cmd"
+exec $cmd