chore(custodian): onboard repo-registry to Custodian State Hub

- Register under capabilities domain (foerster_capabilities renamed)
- Replace prose workplans with ADR-001 format (RREG-WP-0001 done, RREG-WP-0002 active)
- Add AGENTS.md for Codex agent state-hub integration via HTTP API
- Add SCOPE.md with domain context and v0.1 scope boundaries

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SCOPE.md

@@ -0,0 +1,48 @@
+---
+domain: capabilities
+repo: repo-registry
+updated: "2026-04-26"
+---
+
+# repo-registry — Scope
+
+## Purpose
+
+Repository Ability Registry. Turns Git repositories into reviewable, source-linked
+maps of `Ability → Capability → Feature → Evidence`.
+
+## Core Design Principle
+
+```
+deterministic scanners  →  observed facts  (file paths, languages, API routes, …)
+LLM-assisted extractors →  interpreted claims  (ability names, descriptions, links)
+human / agent review    →  approved registry truth
+```
+
+Approved entries are always explicit, reviewable, and source-linked. The system
+never publishes unapproved claims as canonical truth.
+
+## In Scope (v0.1)
+
+- Repository registration by Git URL
+- Deterministic repository scan (file tree, languages, frameworks, API/CLI surface)
+- Candidate extraction for abilities, capabilities, features, and evidence
+- Human review workflow: edit, approve, reject, merge, relink
+- Natural-language and semantic search over approved registry entries
+- REST API for repositories, ability maps, capabilities, and search
+
+## Out of Scope (v0.1)
+
+- Continuous GitHub App integration
+- Full static code understanding (AST/type analysis)
+- Advanced ontology enforcement
+- Distributed indexing
+- Benchmark execution
+- Marketplace or commercial features
+- Complex access control
+- Automated truth claims without review
+
+## Domain Context
+
+Part of the **capabilities** domain — systematic modeling of abilities, capabilities,
+and features across the Custodian ecosystem. First registered repo in this domain.