AIFW-24958: connection status unspecified not handled in event model enum

[vokit-cisco]

Summary

Adds support for the API value ConnectionStatusUnspecified in management connection models.

This change prevents parsing failures when connection or expanded event responses include an unspecified connection status. It adds enum coverage, validates the behavior through connection and event client unit tests, and updates one management example call to match the current event conversation API signature.

Changes

• Added ConnectionStatus.Unspecified enum value mapped to ConnectionStatusUnspecified.
• Added unit test coverage for get_connection() parsing connections with unspecified status.
• Added unit test coverage for expanded event responses containing connections with unspecified status:
  • list_events()
  • get_event()
• Updated management_client_usage.py to call get_event_conversation(first_event.event_id) without the removed/unsupported expanded=True argument.

Test Plan

• Branch diff inspected against main.
• Targeted test files identified:
  • aidefense/tests/test_connection_management_client.py
  • aidefense/tests/test_event_management_client.py

Compatibility Notes

• Additive change: Adds a new enum member without changing existing enum values.
• Client code: Existing callers continue to work; responses containing ConnectionStatusUnspecified now parse correctly.
• Integration impact: Low risk. This fixes handling for an API value that can already appear in responses.

Files Modified

• aidefense/management/models/connection.py - Added ConnectionStatus.Unspecified.
• aidefense/tests/test_connection_management_client.py - Added connection parsing test for unspecified status.
• aidefense/tests/test_event_management_client.py - Added expanded event parsing tests for unspecified connection status.
• examples/management/management_client_usage.py - Updated get_event_conversation() example call.

Total: 86 insertions(+), 1 deletion(-)