Complete REUSE-WP-0003: registry CLI, docs alignment, and coverage

Align INTENT.md with delivered layout, add CapabilityRegistryConcept guide,
extend schema with promotion_history, ship reuse-surface validate/query/export
CLI, register three more helix_forge capabilities, and refresh SCOPE and gap
analysis to reflect A3 tooling and D5/A3/C4/R2 self-assessment.

registry/indexes/capabilities.yaml

@@ -7,13 +7,13 @@ capabilities:
   - id: capability.registry.register
     name: Capability Registration
     summary: Register a new capability so it becomes visible for planning and implementation reuse.
-    vector: D3 / A0 / C1 / R0
+    vector: D3 / A3 / C2 / R2
     domain: helix_forge
     status: draft
     owner: reuse-surface
     path: registry/capabilities/capability.registry.register.md
     tags: [registry, governance, meta]
-    consumption_modes: [informational, markdown authoring]
+    consumption_modes: [informational, markdown authoring, cli]
 
   - id: capability.feature-control.evaluate
     name: Feature Availability Evaluation
@@ -26,6 +26,17 @@ capabilities:
     tags: [feature-control, evaluation, sdk]
     consumption_modes: [SDK, service API]
 
+  - id: capability.feature-control.rollout
+    name: Feature Rollout Control
+    summary: Gradually expose features to subjects across tenants, domains, groups, or cohorts using rollout rules and staged availability.
+    vector: D4 / A2 / C2 / R1
+    domain: helix_forge
+    status: draft
+    owner: feature-control
+    path: registry/capabilities/capability.feature-control.rollout.md
+    tags: [feature-control, rollout, planning]
+    consumption_modes: [source module, SDK]
+
   - id: capability.identity.vocabulary-canonicalize
     name: Identity Vocabulary Canonicalization
     summary: Define and maintain an implementation-neutral vocabulary for identity-related concepts across overlapping domains.
@@ -35,4 +46,26 @@ capabilities:
     owner: identity-canon
     path: registry/capabilities/capability.identity.vocabulary-canonicalize.md
     tags: [identity, terminology, research]
-    consumption_modes: [informational]
+    consumption_modes: [informational]
+
+  - id: capability.identity.subject-resolution
+    name: Identity Subject Resolution
+    summary: Resolve who or what is acting in a context by mapping principals, accounts, actors, and identifiers to a stable subject model.
+    vector: D3 / A0 / C1 / R0
+    domain: helix_forge
+    status: draft
+    owner: identity-canon
+    path: registry/capabilities/capability.identity.subject-resolution.md
+    tags: [identity, subject, architecture]
+    consumption_modes: [informational]
+
+  - id: capability.statehub.workstream-coordinate
+    name: Workstream And Task Coordination
+    summary: Track active workstreams, tasks, progress, and consistency across domain repositories through a local-first coordination service.
+    vector: D4 / A4 / C3 / R2
+    domain: helix_forge
+    status: draft
+    owner: state-hub
+    path: registry/capabilities/capability.statehub.workstream-coordinate.md
+    tags: [state-hub, coordination, workplans]
+    consumption_modes: [service API, HTTP REST]