STATE-WP-0069 T03: normalize MCP progress events to workplan_id

_emit_progress_event strips legacy workstream_id from POST /progress/
payloads. Task and decision side-effect events now set workplan_id
explicitly so automatic progress logging stays workplan-first.

tests/test_mcp_legacy_deprecation.py

@@ -5,6 +5,28 @@ import json
 import mcp_server.server as server
 
 
+def test_normalize_progress_body_prefers_workplan_id_only() -> None:
+    body = server._normalize_progress_body({
+        "workplan_id": "wp-1",
+        "workstream_id": "wp-1",
+        "event_type": "note",
+        "summary": "test",
+    })
+    assert body == {
+        "workplan_id": "wp-1",
+        "event_type": "note",
+        "summary": "test",
+    }
+
+    legacy_only = server._normalize_progress_body({
+        "workstream_id": "wp-legacy",
+        "event_type": "note",
+        "summary": "legacy",
+    })
+    assert legacy_only["workplan_id"] == "wp-legacy"
+    assert "workstream_id" not in legacy_only
+
+
 def test_legacy_mcp_deprecation_payload_names_replacement() -> None:
     payload = server._legacy_mcp_deprecation(tool="create_workstream")
     assert payload["replacement"] == "create_workplan"