Function detect_instance_changes 

pub fn detect_instance_changes(
    namespace: &str,
    name: &str,
    watch_instances: Option<&Vec<InstanceReference>>,
    current_instances: &[InstanceReference],
) -> bool

Detect if the instance list changed between watch event and re-fetch.

This is critical for detecting when:

1. New instances are added to status.bind9Instances (via bind9InstancesFrom selectors)
2. Instance lastReconciledAt timestamps are cleared (e.g., instance deleted, needs reconfiguration)

NOTE: InstanceReference PartialEq ignores lastReconciledAt, so we must check timestamps separately!

Arguments

• namespace - Namespace for logging
• name - Zone name for logging
• watch_instances - Instances from the watch event that triggered reconciliation
• current_instances - Instances after re-fetching (current state)

Returns

true if instances changed (list or timestamps), false otherwise