Restore dice assignment, fusion, and the commitment counterweights

The ship40 concept pipeline had reversed the proven a-series mechanisms:
the seed's roll decayed into a shortlist nomination that taste functions
(model ranking, candidate floor, simulated user) then argmaxed into the
safest card; the costume check returned as the Translation veto and
carrier-removal test; and the 07-15 rewrite deleted the calibration,
reflex-font lanes, color strategies, and commit-every-atom language that
had held off the cream-editorial default since the alpha era. Five of six
frozen craft directions converged on the same warm-paper family and both
builders obeyed them.

This lands the repair on top of the in-progress simplification:

- new-work.md: the script assigns the build index again on both scopes;
  catalog challengers are fused (challenger supplies form and grammar,
  product supplies every fact, clarity wins conflicts) and weighed on the
  two proven axes only; attended runs present one fully committed
  direction with re-roll and an optional steer instead of a ranked
  lineup; the color-strategy picker, reflex-face list, saturated-look
  calibration, first-viewport thesis and memory test, commit-every-atom,
  scroll pacing, and prove-don't-claim return; the direction contract
  returns as five lean blocks audited by the separate-agent finish.
- concept-seed.mjs: PROMOTED INDEX becomes ASSIGNED INDEX with
  build-assignment semantics; self re-roll only on named factual grounds.
- craft-floor.md: hook-active sessions act on findings instead of
  re-auditing; the Refuse list is framed as category defaults the brief
  can earn; a closing commitment line keeps a ban list from being the
  last word before code.
- codex.md / shape.md: contract references restored for flow coherence.

Adopts the concurrent session's ceremony cuts, softened challenger
instruction, seed SOURCE IDs and --candidate-count, detector-ownership
fix, and the removal of the hook-side contract audit (the audit now
belongs to the separate reviewer at finish).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skill/reference/shape.md

@@ -2,8 +2,6 @@
 
 Discover what should be made and how it should work, then return a confirmed design brief without code.
 
-**Product gate:** when context reports that PRODUCT.md is missing, load and complete [init.md](init.md) before Phase 1. Do not substitute shape questions for the product interview. Once PRODUCT.md exists, return here; product context does not replace task discovery.
-
 ## Phase 1: Discovery interview
 
 Do not write code or choose visual direction yet.