fix(gateway): B4 decision/reflect remediate includes literal call example

Smoke run 3 showed Main PM taking 7 attempts to satisfy the decision-note
required-fields contract — the remediate listed which fields were
missing but didn't show what a fully-formed call looks like. The LLM
pattern-matches examples better than field-list prose; each retry it
dropped a different field.

Added a literal note(scope='decision', ...) / note(scope='reflect', ...)
call template to the rejection remediate so the agent sees the canonical
shape with named-keyword args and example values. The missing-fields
list stays — both pieces of information are useful, but the example is
what actually drives convergence.

Spec ref: docs/superpowers/specs/2026-05-12-post-smoke-3-fixes-design.md
section B4.

tests/unit/gateway/test_content_actions.py

@@ -646,3 +646,56 @@ async def test_verify_explicit_task_ownership_returns_not_found() -> None:
     assert env is not None
     body = env.as_dict()
     assert body["error"] == "not_found"
+
+
+# ---------------------------------------------------------------------------
+# B4 — decision/reflect remediate includes a literal call example
+# ---------------------------------------------------------------------------
+
+
+@pytest.mark.asyncio
+async def test_decision_incomplete_input_includes_call_example() -> None:
+    """Decision rejection includes a literal note(scope='decision', ...) template."""
+    task = AsyncMock()
+    task.get_active_task_for_agent.return_value = None
+    task.agent_for.return_value = MagicMock(role="cell_pm")
+    deps = _make_deps(task=task)
+    ca = ContentActions(deps)
+
+    env = await ca.note(
+        agent_id=uuid4(),
+        text="bare decision",
+        scope="decision",
+    )
+    body = env.as_dict()
+    assert body["error"] == "incomplete_input"
+    remediate = body.get("remediate", "")
+    # Must include a literal call template, not just a field list
+    assert "note(scope='decision'" in remediate, remediate
+    assert "context=" in remediate, remediate
+    assert "options=[" in remediate, remediate
+    assert "chosen=" in remediate, remediate
+    assert "rationale=" in remediate, remediate
+
+
+@pytest.mark.asyncio
+async def test_reflect_incomplete_input_includes_call_example() -> None:
+    """Reflect rejection includes a literal note(scope='reflect', ...) call template."""
+    task = AsyncMock()
+    task.get_active_task_for_agent.return_value = None
+    task.agent_for.return_value = MagicMock(role="developer")
+    deps = _make_deps(task=task)
+    ca = ContentActions(deps)
+
+    env = await ca.note(
+        agent_id=uuid4(),
+        text="bare reflect",
+        scope="reflect",
+    )
+    body = env.as_dict()
+    assert body["error"] == "incomplete_input"
+    remediate = body.get("remediate", "")
+    assert "note(scope='reflect'" in remediate, remediate
+    assert "what_done=" in remediate, remediate
+    assert "what_learned=" in remediate, remediate
+    assert "what_struggled=" in remediate, remediate