chore(wp-0001): close State Hub bootstrap workplan; de-template repo identity

- repo-identity.md / repo-boundary.md: replace leftover repo-seed template text
  with secrets-engine identity and boundary (T01)
- mark SECRETS-WP-0001 T01–T03 done (T02 dev-workflow commands and T03 first real
  workplan were completed during the MVP build); workplan status -> finished

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

workplans/SECRETS-WP-0001-statehub-bootstrap.md

@@ -4,7 +4,7 @@ type: workplan
 title: "Bootstrap State Hub integration"
 domain: infotech
 repo: secrets-engine
-status: ready
+status: finished
 owner: codex
 topic_slug: custodian
 created: "2026-06-28"
@@ -20,7 +20,7 @@ secrets-engine is a headless, multi-application, multi-tenant secrets workflow a
 
 ```task
 id: SECRETS-WP-0001-T01
-status: todo
+status: done
 priority: high
 state_hub_task_id: "e93ea995-8c3b-4892-ab09-70cf7e0a0346"
 ```
@@ -32,7 +32,7 @@ Replace generated placeholders with repo-specific facts where needed.
 
 ```task
 id: SECRETS-WP-0001-T02
-status: todo
+status: done
 priority: high
 state_hub_task_id: "3269b817-6e10-4e9f-804f-73a8b1ded920"
 ```
@@ -45,7 +45,7 @@ changes confidently.
 
 ```task
 id: SECRETS-WP-0001-T03
-status: todo
+status: done
 priority: medium
 state_hub_task_id: "62de7242-1a4c-4ed0-a4e4-ebe17bcc06b6"
 ```