feat(terminology): prose sweep tool and custodian workplan cleanup (CUST-WP-0055 T04)

Add sweep_workstream_prose.py for agent-guidance files, sweep active workplan
prose in-repo, tighten scan allowlist exclusions, and update ADR-001 closure
protocol to workplan-first terminology.

agents/agent-scope-analyst.md

@@ -14,7 +14,7 @@ This agent is now primarily a routing shim:
 
 - inspect the target repository enough to decide whether a new SCOPE.md is
   needed or an existing one should be refreshed;
-- when tied to a State Hub workstream or task, prefer `get_flow_state()` for
+- when tied to a State Hub workplan or task, prefer `get_flow_state()` for
   lifecycle orientation and `advance_workstation()` for flow-aware movement
   after requisite assertions are satisfied;
 - prefer `scope.generate` when no SCOPE.md exists or the file is only a stub;
@@ -36,7 +36,7 @@ request_capability(
     capability_type="api",
     requesting_agent="scope-analyst",
     requesting_domain="custodian",
-    requesting_workstream_id="<workstream-uuid>",
+    requesting_workstream_id="<workplan-uuid>",
     priority="medium",
 )
 ```