Golden actor: activation-ready preflight and user handoff

[svelderrainruiz]

Parent epic: #442

Problem

The golden actor build/install scripts establish prerequisites, but the point at which a user can safely take over for NI activation is scattered across scripts and prose.

Deliverable

Create a non-secret golden actor readiness preflight and activation handoff that:

• checks the real guest for LabVIEW, VIPM, Xvfb, VI Server configuration, and the activation probe prerequisites;
• distinguishes provisioned/unactivated, activation-ready, and activation-confirmed states;
• produces a deterministic, non-secret readiness receipt;
• gives the user a concise explicit handoff only when interaction is actually required;
• never accepts or routes NI credentials through automation.

Acceptance

• A repeatable local validation covers success and fail-closed prerequisite cases.
• The readiness flow can be invoked by the extension workflow or documented command path.
• The PR documents exact host/guest validation evidence.