L03-13f — Add soft proofing and interactive separations to Production Preview #237

Outcome

Production Preview simulates the output intent (paper white, gamut) and lets the operator isolate plates, replacing the retired output-preview and soft-proofing plugins.

Parent and boundary

Parent: #231. Owner: LoopEditor. This issue owns one bounded slice of Quick Workspace; consume accepted upstream contracts and keep PDF/verdict/publication authority with Core.

Grounding

• docs/product-surface.json absorbs output-preview-plugin and soft-proofing-plugin into loop-production-preview.
• ProductionPreviewPane.qml lists plates read-only and offers an exact-overprint render; there is no plate visibility control and no soft-proof reference in LoopEditor or LoopLibQuick.
• L03-02 — Separate Production Preview from fast canvas #28 (L03-02) owns fidelity and origin labelling, not soft proofing.

Acceptance

• Soft proof renders through Core's color management with the profile identity shown; the fidelity indicator marks it as a simulation.
• Each plate can be shown alone or hidden, with ink coverage readout at a point.
• A soft-proof or isolated-plate view is never recorded as approval evidence.
• Failure case: a missing or invalid output-intent profile is a visible state, never a silent fallback to sRGB.

Required proof

Render comparison against reference separations on CMYK + spot fixtures; profile-missing fixture; quick lane. Record the exact source SHA, test command or hosted run, fixture/artifact identity, and any skipped or unavailable lane. Run the repository's mapped proof and check-change gate for a PR.

Handoff

Record changed files, observed result, remaining risk, and a 1–3 sentence anti-slop review. Completion means acceptance evidence, not merely a merged implementation.

Sources

Approved master roadmap · Gap review of docs/loop-shell-actions.json against Quick command handlers, 2026-10-06.