Add State Hub bootstrap workplan and agent integration files

Seed workplans/ with bootstrap workplan to satisfy ADR-001 C-01.
Includes regenerated dev-hub session-protocol and agent instruction files.

.claude/rules/architecture.md

@@ -0,0 +1,8 @@
+## Architecture
+
+<!-- TODO: Describe the key design decisions and component structure.
+     Key modules, data flows, external integrations, state machines, etc. -->
+
+## Quick Reference
+
+`~/state-hub/mcp_server/TOOLS.md` — MCP tool reference