Decision: ViewRep is trusted to be internally consistent. Consumers downstream of a ViewRep field — SwiftUI views, ViewRep sub-mappers — may assume any state implied by the ViewRep is present (for example, if a ViewRep case names a selected movie, the matching movie entry exists) and fatalError() if it isn't. Silent degradation — a placeholder view, an empty-state fallback, an optional return unwrapped to a default — is the wrong fix. The invariants that keep ViewRep valid are enforced upstream by the StateMachine and pinned by fluent unit tests (ADR-002, ADR-003); a violation is a bug to surface, not to hide.
Optional return types remain appropriate for genuine "nothing to render" cases driven by user toggles or nil-in / nil-out passthroughs — not for required state that the ViewRep is supposed to guarantee.
Drops findings that ask ViewRep consumers to gracefully degrade (return a placeholder, fall back to an empty state, or make a required field optional) instead of fatalError()-ing on a missing invariant. Strengthens findings about types whose doc-comments claim a contract their signature doesn't enforce (default-valued parameters papering over a "required" field, optional properties the code treats as non-optional) — encode invariants in the type, not the comment.