feat: route workflow image inputs natively

backend/services/workflow/routing.py

@@ -3,6 +3,7 @@
 from __future__ import annotations
 
 from collections.abc import Callable
+from typing import Any
 
 from services.runtime_variables import DynamicVariableStore
 from services.workflow.models import EdgeEvaluation, RouteStatus
@@ -23,7 +24,12 @@ class WorkflowEdgeEvaluator:
         self._store = store
         self._router_for_node = router_for_node
 
-    async def evaluate(self, node_id: str) -> EdgeEvaluation:
+    async def evaluate(
+        self,
+        node_id: str,
+        *,
+        current_user_message: dict[str, Any] | None = None,
+    ) -> EdgeEvaluation:
         """Select the first matching conditional path, then the default path."""
         outgoing = self._engine.outgoing(node_id)
         expression_edge = self._engine.deterministic_edge(
@@ -61,6 +67,7 @@ class WorkflowEdgeEvaluator:
             node_prompt=self._engine.routing_prompt(node_id, self._store),
             edges=llm_edges,
             history=self._store.history,
+            current_user_message=current_user_message,
             variables={
                 key: value
                 for key, value in self._store.values.items()
@@ -94,4 +101,3 @@ class WorkflowEdgeEvaluator:
         if edge is None:
             return EdgeEvaluation(status=RouteStatus.NO_MATCH)
         return EdgeEvaluation(status=RouteStatus.MATCHED, edge=edge)
-