chore(custodian): add CLAUDE.md and .claude/rules/ orientation files

Registers llm-connect with the Custodian agent system:
- CLAUDE.md: thin @-import index pointing to modular rules
- .claude/rules/session-protocol.md: orient with get_domain_summary("custodian")
- .claude/rules/repo-identity.md: domain=custodian, slug=llm-connect
- .claude/rules/first-session.md, workplan-convention.md, stack-and-commands.md,
  architecture.md, repo-boundary.md, agents.md, scope.md (stubs to fill in)
- session-protocol notes both local (:8000) and CoulombCore bridge (:18000) URLs

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

CLAUDE.md

@@ -0,0 +1,11 @@
+# llm-connect — Claude Code Instructions
+
+@SCOPE.md
+@.claude/rules/repo-identity.md
+@.claude/rules/session-protocol.md
+@.claude/rules/first-session.md
+@.claude/rules/workplan-convention.md
+@.claude/rules/stack-and-commands.md
+@.claude/rules/architecture.md
+@.claude/rules/repo-boundary.md
+@.claude/rules/agents.md