VSA: Add value stream usage tracking

Proposal

Implement controller-level tracking to identify which value streams are actively used, capturing both direct navigation and dropdown selections.

track_internal_event(
  "view_value_stream_analytics",
  user: user,
  additional_properties: {
    label: value_stream_name,
    value: value_stream_id
  }
)

It should only be triggered by the show controller action when a value stream exists.