docs(policy): add Repository Definition of Integrated (DoI)

Three-tier checklist defining what 'fully integrated with the state-hub'
means for a repository:
- Core (Registered): registered, domain assigned, path resolves, remote URL
- Standard (Integrated): SCOPE.md, CLAUDE.md, workplan convention, SBOM, TPSC
- Full (Fully Integrated): repo goal, capabilities declared, agents template,
  clean consistency check, host paths registered

Exposed via /policy/repo-doi (editable in dashboard) and linked under Policies.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

state-hub/dashboard/observablehq.config.js

@@ -33,6 +33,7 @@ export default {
       collapsible: true,
       open: false,
       pages: [
+        { name: "Repository DoI",  path: "/policy/repo-doi" },
         { name: "Workstream DoD", path: "/policy/workstream-dod" },
       ],
     },