Keel v2.1.0

Added

• The handoff directory is exclusively Design's delivery — wholesale-replaceable, always (handoff contract, new rule 10; field-tested). Nothing but the delivered bytes ever lives in docs/design/design-handoff/: no generated assets, no user-acquired fonts, no notes or audit evidence, no build output. The reason is operational: installing a delivery or a re-delivery is a whole-directory swap — archive the current delivery to docs/old/design-handoff/<DR-id-or-date>/ (move, never delete), place the new one, diff against the archived copy — and a single foreign file makes that swap unsafe and blocks it, which had repeatedly happened in the field. Phase 4 gains the matching non-negotiable rule (its seventh), its Step 1 mechanical pass now flags any file the delivery's own SPEC does not account for, and Step 6 targets the PROJECT's asset tree for user-generated assets and acquired fonts (the font acquisition block's target path is now explicitly a project path, with the delivered @font-face referencing that final path). Phase 3 states the rule at the exact moment the returned handoff is placed.