refactor: Migrate from monolithic to modular architecture

- Restructure project into domain-specific modules (core, masterdata, members, horses, events, infrastructure)
- Create shared client components in common-ui module
- Implement CI/CD workflows with GitHub Actions
- Consolidate documentation in docs directory
- Remove deprecated modules and documentation files
- Add cleanup and migration scripts for transition
- Update README with new project structure and setup instructions

cleanup_old_modules.sh

@@ -0,0 +1,53 @@
+#!/bin/bash
+
+# Script to remove old module directories after successful migration
+# This script should be run after verifying that all new modules build successfully
+#
+# Usage:
+#   ./cleanup_old_modules.sh         # Remove old module directories
+#   ./cleanup_old_modules.sh --dry-run  # Show what would be removed without actually removing
+
+set -e  # Exit on error
+
+# Check for dry run mode
+DRY_RUN=false
+if [ "$1" == "--dry-run" ]; then
+    DRY_RUN=true
+    echo "Running in DRY RUN mode - no files will be deleted"
+fi
+
+echo "Starting cleanup of old module directories..."
+
+# List of old module directories to remove
+OLD_MODULES=(
+    "shared-kernel"
+    "master-data"
+    "member-management"
+    "horse-registry"
+    "event-management"
+    "api-gateway"
+    "composeApp"
+)
+
+# Check if directories exist and remove them
+for module in "${OLD_MODULES[@]}"; do
+    if [ -d "$module" ]; then
+        if [ "$DRY_RUN" = true ]; then
+            echo "[DRY RUN] Would remove old module directory: $module"
+        else
+            echo "Removing old module directory: $module"
+            rm -rf "$module"
+        fi
+    else
+        echo "Module directory not found: $module (already removed)"
+    fi
+done
+
+if [ "$DRY_RUN" = true ]; then
+    echo "Dry run completed. No files were deleted."
+    echo "To actually remove the directories, run the script without the --dry-run option."
+else
+    echo "Cleanup completed successfully!"
+    echo "All old module directories have been removed."
+    echo "The migration is now complete."
+fi