Proposal 1 — T14: dedup + selective composition

pkl: Derive workflow Related Units and compose profiles selectively

Give every normative rule one authoritative section. composeProfile now
amends the workflow body and overrides only Preconditions, Guardrails,
and Failure handling with the profile fragment, leaving Purpose, Inputs,
Workflow, and Outputs exactly as authored. Related Units become
metadata-derived (bound profile, entry skill, then remaining required
skills) with authored relatedUnits reduced to non-derivable extras;
OpenCode native workflows render nativeWorkflowBody so they carry the
same derived relations. Removes the dead sharedSce* baseline constants
and regenerates every next-task/change-to-plan/commit/handover/validate
projection, shrinking committed instruction Markdown by ~390 lines.

Co-authored-by: SCE <sce@crocoder.dev>

Author: davidabram