S1a (rev-3 amendment): build returns to the picker — plan · build · develop · research #868

Important

Problem — S1 (#862) removed build from the picker per the spec's original D1 ('auto implied'). Real usage (2026-09-07, Aaron): build is the plain-work mode — authoring proposal decks, one-off fixes — distinct from develop's campaign machinery. Removing it was wrong; it's used daily.
Approach — The spec amendment (spec-20260907-011500 rev 3, D1 revised): the picker lists plan · build · develop · research in that order; build is a named, selectable tile AND remains the default posture (marked default, not implied-absent). develop/research stay the campaign postures; the plan-exit recommendation (S2, landed #864) never targets build — build is the resting state, not a recommendation target. No auto-router mode.