refactor(docs): split CLAUDE.md into scoped rules files under .claude/rules/

Each concern (identity, session protocol, workplan convention, stack,
architecture, repo boundary) now lives in its own file with a single
responsibility. CLAUDE.md becomes a thin @-import integrator. Removes
Ralph Loop duplication — global ~/.claude/CLAUDE.md remains authoritative.

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

.claude/rules/session-protocol.md

@@ -0,0 +1,24 @@
+## Custodian State Hub Integration
+
+State Hub: http://127.0.0.1:8000
+
+### Session Protocol
+
+**Step 1 — Orient**
+```
+get_domain_summary("custodian")
+```
+
+**Step 2 — Scan workplans**
+```
+ls workplans/
+```
+
+**During work:** use `record_decision()`, `add_progress_event()`, `resolve_decision()`.
+
+**Session close:** `add_progress_event()` with workstream_id.
+
+If workplan files were modified, run from `~/the-custodian/state-hub/`:
+```bash
+make fix-consistency REPO=ops-bridge
+```