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.

templates/capability-entry.template.md

@@ -78,6 +78,15 @@ consumer_guidance:
     - describe unsafe or weak reuse scenarios
   known_limitations:
     - list known gaps, risks, or missing evidence
+
+# Optional: append a row when a maturity dimension is promoted with evidence.
+promotion_history: []
+#  - date: "2026-06-15"
+#    dimension: discovery
+#    from: D0
+#    to: D1
+#    rationale: Added intent, summary, and basic actors.
+#    author: capability-owner
 ---
 
 # Example Capability