Add purpose and demand model extension

infospace/agent/templates/canon-interface-card.template.yaml

@@ -7,7 +7,11 @@ consumer:
   owner: ''
   intent: ''
   scope: ''
-  purposes: []
+  purposes:
+  - id: ''
+    use_case: ''
+    consumer_need: ''
+    demand_signals: []
 canon_surfaces:
   implemented_profiles: []
   consumed_artifacts: []
@@ -19,6 +23,11 @@ validation_expectations:
   commands: []
   evidence_required: []
   known_gaps: []
+purpose_fit:
+  state: ''
+  matched_capabilities: []
+  scope_pressure: ''
+  recommended_disposition: ''
 consumer_needs:
   current: []
   requested_extensions: []