feat(terminology): workplan-first dashboard and retirement backlog (STATE-WP-0069)

Add the ranked legacy-interface backlog (T01), rename dashboard navigation and
user-facing copy to workplan while preserving wire-compat API keys (T02), and
activate the retirement workplan with T01/T02 marked done.

dashboard/src/data/workstreams/[id].json.py

@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-"""Observable data loader: fetches a single workstream by ID."""
+"""Observable data loader: fetches a single workplan by ID."""
 import json
 import os
 import sys
@@ -11,7 +11,7 @@ API_BASE = os.environ.get("API_BASE", "http://127.0.0.1:8000").rstrip("/")
 ws_id = sys.argv[1] if len(sys.argv) > 1 else ""
 
 if not ws_id:
-    print(json.dumps({"error": "No workstream ID provided"}))
+    print(json.dumps({"error": "No workplan ID provided"}))
     sys.exit(1)
 
 try: