Complete REUSE-WP-0005: registry federation and relation graphs

Add federation manifest and schema, federation compose and graph CLI commands,
relation cycle/reference checks, federated index and Mermaid graph artifacts,
RegistryFederation guide, and CI validation updates.

workplans/REUSE-WP-0005-registry-federation.md

@@ -4,7 +4,7 @@ type: workplan
 title: "Registry federation and relation graphs"
 domain: helix_forge
 repo: reuse-surface
-status: ready
+status: finished
 owner: codex
 topic_slug: helix-forge
 created: "2026-06-15"
@@ -34,7 +34,7 @@ from configured sources and generating relation graphs for architects (UC-RS-016
 
 ```task
 id: REUSE-WP-0005-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "9a9732ea-c546-49fe-bf61-0f3bdf94406a"
 ```
@@ -55,7 +55,7 @@ Include commented placeholders for `state-hub`, `feature-control`, and
 
 ```task
 id: REUSE-WP-0005-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "9539c609-ac44-40a7-90bc-6f294fe085b9"
 ```
@@ -73,7 +73,7 @@ and writes `registry/indexes/federated.yaml`. Requirements:
 
 ```task
 id: REUSE-WP-0005-T03
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "4f7e85a5-c73a-49b6-a044-ba1fabc54d8a"
 ```
@@ -90,7 +90,7 @@ entry relations. Requirements:
 
 ```task
 id: REUSE-WP-0005-T04
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "6f7e2913-9634-4ebb-841f-9024b35961ef"
 ```
@@ -105,7 +105,7 @@ Extend validation or graph generation to report:
 
 ```task
 id: REUSE-WP-0005-T05
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "8d69121b-9961-41c2-8802-d9c5b5d94c69"
 ```