Implement REUSE-WP-0012 federation scale and intent alignment

Add hub sync and report cohorts CLI commands with pytest coverage, document
sibling index publish contract and hub hardening path, align INTENT layout,
raise external evidence on three registry entries, and close gap priorities
19-23 (priority 18 deferred on sibling index blocks).

registry/capabilities/capability.statehub.progress-log.md

@@ -32,11 +32,16 @@ external_evidence:
     out_of_scope_expectations:
       - replacing git commit history
   reliability:
-    level: R2
-    confidence: low
+    level: R3
+    name: Usable
+    confidence: medium
     basis: consumer_quality_signals
     known_reliability_risks:
-      - depends on hub availability
+      - depends on hub availability and tunnel health for remote agents
+    evidence:
+      satisfied_signals:
+        - reuse-surface AGENTS.md session-close protocol cites POST /progress/
+        - cross-repo agents log progress with workstream_id linkage
 
 discovery:
   intent: Provide auditable progress memory for cross-repo agent and operator work.
@@ -63,6 +68,14 @@ relations:
   related_to:
     - capability.statehub.workstream-coordinate
 
+evidence:
+  documentation:
+    - AGENTS.md
+  consumer_feedback:
+    - >
+        reuse-surface agents (REUSE-WP-0012): session-close progress posts to State
+        Hub succeeded for workstream fb0b6067 during federation workplan work.
+
 consumer_guidance:
   recommended_for:
     - closing agent sessions with hub progress notes