Refine travel reimbursement steward flow

Align planner, runtime rules, and policy assets so travel guidance
matches the updated reimbursement workflow.

server/tests/test_steward_intent_agent.py

@@ -0,0 +1,30 @@
+from app.services.steward_intent_agent import (
+    STEWARD_INTENT_FUNCTION_NAME,
+    StewardIntentAgent,
+)
+
+
+def test_steward_intent_tool_schema_supports_pending_flow_confirmation() -> None:
+    schema = StewardIntentAgent._build_intent_tool_schema(
+        ["expense_type", "time_range", "location", "reason", "transport_mode"]
+    )
+
+    function_schema = schema["function"]
+    assert function_schema["name"] == STEWARD_INTENT_FUNCTION_NAME
+    properties = function_schema["parameters"]["properties"]
+    pending_schema = properties["pending_flow_confirmation"]
+    candidate_schema = pending_schema["properties"]["candidate_flows"]["items"]
+
+    assert "pending_flow_confirmation" in properties
+    assert pending_schema["properties"]["status"]["enum"] == ["none", "pending"]
+    assert candidate_schema["properties"]["flow_id"]["enum"] == [
+        "travel_application",
+        "travel_reimbursement",
+    ]
+    assert candidate_schema["properties"]["missing_fields"]["items"]["enum"] == [
+        "expense_type",
+        "time_range",
+        "location",
+        "reason",
+        "transport_mode",
+    ]