feat: plan agent v2, global chat mode, and user-mode v2 flag sync

- Add runtime/plan_agent_v2 package and shims; gateway/direct_loop/WS wiring

- Admin chat: interaction mode and specialist only in user menu; session API stores memory_mode and execution_mode only

- POST /admin/api/chat/user-mode mirrors plan_agent_version to AIA_EXPERT_PLAN_AGENT_V2_ENABLED (v2 to 1, v1 to 0)

- Composer cleanup (hidden mode select, no reasoning toggle in meta bar); tests and _local/system.env.example

Co-authored-by: Cursor <cursoragent@cursor.com>

runtime/plan_agent_v2/trace.py

@@ -0,0 +1,37 @@
+from __future__ import annotations
+
+import time
+from typing import Any
+
+
+def emit_plan_agent_v2_trace(
+    *,
+    store: Any,
+    session_id: str,
+    trace_id: str | None,
+    parent_span_id: str | None,
+    event_type: str,
+    payload: dict[str, Any] | None = None,
+) -> None:
+    if not str(trace_id or "").strip():
+        return
+    merged = dict(payload or {})
+    merged.setdefault("pipeline", "plan_agent_v2")
+    merged.setdefault("ts_ms", int(time.time() * 1000))
+    try:
+        from oclaw.runtime.orchestration.trace import new_span_id
+
+        store.add_trace_event(
+            session_id=str(session_id or ""),
+            trace_id=str(trace_id),
+            span_id=new_span_id(),
+            parent_span_id=parent_span_id,
+            event_type=str(event_type or "plan_agent_v2"),
+            payload=merged,
+        )
+    except Exception:
+        pass
+
+
+__all__ = ["emit_plan_agent_v2_trace"]
+