v2.1.0 — /aep-model object-first design stage (OOUX/ORCA)

Add an object-first design stage — /aep-model — that turns the verb-first
story map into a noun-first Object Map (OOUX/ORCA) before UI is built, so build
agents stop inventing one-step-one-screen task-wizard UIs. The structural UI plan
(objects, attributes, relationships, CTAs, screens) is auto-drafted from artifacts
AEP already produces, human-approved at a short gate, then governs build — leaving
only taste (look/voice/journey) to /aep-calibrate. Background and the verb-first
vs noun-first analysis: docs/research/ooux-object-modeling.md.

Added

• /aep-model skill (product-context): runs ORCA (Objects → Relationships →
  Calls-to-action → Attributes → screens) to draft an Object Map, takes a short
  human review gate (object boundaries, primary anchor, task-flow exceptions), and
  writes the approved noun-first blueprint. Sits between /aep-map and
  /aep-dispatch for UI-facing products. Registered in
  marketplace.json product-context plugin.
• Object Map artifacts + schemas: product/object-model.yaml (cross-capability
  object ontology) and product/maps/<capability>/object-map.yaml (capability-scoped
  ORCA/IA projection), via _shared/templates/object-model-schema.yaml and
  object-map-schema.yaml. Object-first is the default; task-oriented flows are an
  opt-in escape hatch recorded with a reason.
• ORCA reference (product-context/model/references/orca-process.md):
  round-by-round derivation from AEP inputs + the object-first/task-oriented decision
  framework and the completeness checks.
• Glossary terms: Object Model, Object Map, ORCA, Call-to-Action (CTA), Nested
  Object Matrix, Object-First vs Task-Oriented.
• Research note docs/research/ooux-object-modeling.md and a Research category
  in docs/README.md.

Changed

• Schema (product-context-schema.yaml): adds stories[].object_model_refs,
  stories[].capability, architecture.modules[].kind, and the object-model
  quality dimension. Object-map approvals are tracked as thin calibration.history
  references — the artifact bodies stay under product/, not inlined into
  product-context.yaml.
• /aep-envision: declares the object-model structural gate by default for
  UI-facing products.
• /aep-map: auto-drafts Object Maps after decomposition; sets module.kind +
  story.capability; flips an approved map to stale on re-decompose; routes Next
  Step to /aep-model.
• /aep-dispatch: injects the minimal Object Map slice into a story's context
  package and refuses UI-facing stories without an approved (non-stale) map.
• /aep-launch: aborts a UI-facing story when no approved Object Map covers it.
• /aep-build: UI implementation obeys the injected Object Map slice (object structure and CTA grammar; taste still from calibration).
• /aep-validate: Mode A gains Object Map completeness checks (coverage, object
  homes, anchors, task-flow justification, ref resolution).

All additions are backward-compatible — the object-model path only engages for
UI-facing products that opt in.