Explain Django's session framework and configuration.

Django session framework:\n\n**Session Engines:**\n• Database sessions (default)\n• File-based sessions\n• Cache-based sessions\n• Cookie-based sessions\n\n**Configuration:**\n```python\nSESSION_ENGINE = 'django.contrib.sessions.backends.db'\nSESSION_COOKIE_AGE = 1209600 # 2 weeks\nSESSION_COOKIE_SECURE = True # HTTPS only\nSESSION_COOKIE_HTTPONLY = True # No JavaScript access\n```\n\n**Usage:**\n```python\n# Set session data\nrequest.session['key'] = 'value'\n\n# Get session data\nvalue = request.session.get('key')\n\n# Delete session data\ndel request.session['key']\n```\n\n**Security:**\n• Use secure cookies in production\n• Set appropriate expiration\n• Regenerate session ID on login