feat: add SQLite persistent storage for request logging

- Add SQLAlchemy-based database layer for persistent storage
  - Create models for access_logs, credential_attempts, attack_detections, ip_stats
  - Include fields for future GeoIP and reputation enrichment
  - Implement sanitization utilities to protect against malicious payloads
  - Fix XSS vulnerability in dashboard template (HTML escape all user data)
  - Add DATABASE_PATH and DATABASE_RETENTION_DAYS config options
  - Dual storage: in-memory for dashboard performance + SQLite for persistence

  New files:
  - src/models.py - SQLAlchemy ORM models
  - src/database.py - DatabaseManager singleton
  - src/sanitizer.py - Input sanitization and HTML escaping
  - requirements.txt - SQLAlchemy dependency

  Security protections:
  - Parameterized queries via SQLAlchemy ORM
  - Field length limits to prevent storage exhaustion
  - Null byte and control character stripping
  - HTML escaping on dashboard output

src/server.py

@@ -12,6 +12,7 @@ from config import Config
 from tracker import AccessTracker
 from handler import Handler
 from logger import initialize_logging, get_app_logger, get_access_logger, get_credential_logger
+from database import initialize_database
 
 
 def print_usage():
@@ -33,6 +34,8 @@ def print_usage():
     print('  PROBABILITY_ERROR_CODES - Probability (0-100) to return HTTP error codes (default: 0)')
     print('  CHAR_SPACE            - Characters for random links')
     print('  SERVER_HEADER         - HTTP Server header for deception (default: Apache/2.2.22 (Ubuntu))')
+    print('  DATABASE_PATH         - Path to SQLite database (default: data/krawl.db)')
+    print('  DATABASE_RETENTION_DAYS - Days to retain database records (default: 30)')
 
 
 def main():
@@ -49,6 +52,13 @@ def main():
 
     config = Config.from_env()
 
+    # Initialize database for persistent storage
+    try:
+        initialize_database(config.database_path)
+        app_logger.info(f'Database initialized at: {config.database_path}')
+    except Exception as e:
+        app_logger.warning(f'Database initialization failed: {e}. Continuing with in-memory only.')
+
     tracker = AccessTracker()
 
     Handler.config = config