feat: Add mobile compatibility utilities and enhance UI templates

- Introduced mobile compatibility utilities in mobile_compatibility.js for better handling of file uploads and image previews on mobile devices.
- Created base.html as a foundational template with responsive design and mobile compatibility features.
- Developed login.html for user authentication with a password toggle feature.
- Added main.html for displaying license keys and HWIDs with options to generate new keys and upload backups.
- Implemented a test script (test.sh) for validating license information via API.
- Created verify.py for license key validation and management, including functions for loading, checking, and registering keys.
- Added version.txt to track the current version of the application.

Inventarsystem-Lizenz-Verwaltung/backup.py

@@ -0,0 +1,43 @@
+import os
+import json
+from pathlib import Path
+
+LICENSES_FILE = os.path.abspath(os.path.join(os.path.dirname(__file__),"licenses.json"))
+
+
+def load_licenses() -> dict:
+    """Load licenses.json file and return its content."""
+    try:
+        with open(LICENSES_FILE, "r") as f:
+            return json.load(f)
+    except (FileNotFoundError, json.JSONDecodeError):
+        return []
+
+
+def save_licenses(data: dict) -> bool:
+    """Save licenses data to licenses.json file."""
+    try:
+        os.makedirs(os.path.dirname(LICENSES_FILE), exist_ok=True)
+        with open(LICENSES_FILE, "w") as f:
+            json.dump(data, f, indent=2)
+        return True
+    except Exception as e:
+        print(f"Error saving licenses: {e}")
+        return False
+
+
+def export_backup() -> dict:
+    """Export current licenses.json content."""
+    return load_licenses()
+
+
+def import_backup(data: dict) -> bool:
+    """Import and restore licenses from backup data."""
+    try:
+        if not isinstance(data, list):
+            return False
+        save_licenses(data)
+        return True
+    except Exception as e:
+        print(f"Error importing backup: {e}")
+        return False