The Read-only declaration is the first of the lifecycle's two customer-authored milestones. From the user's side it's the operationally important moment — the legacy system stops accepting writes. From the factory's side it's the trigger for Final Capture, the comprehensive run that captures everything not already gathered during the Live Snapshots period and seals it.

The output is the set of Final Snapshots: the permanent, locked, canonical record of truth. Afterward, the SQL components for that Transition become immutable. This is also what gives the Live-vs-Final distinction its meaning: a Live Snapshot taken earlier can be pixel-for-pixel identical to its Final counterpart, but only the Final one carries canonical authority. Everything captured before read-only was provisional; read-only is the moment it gets locked down.