feat: add configurable vision focus prompts

backend/services/workflow/agent.py

@@ -11,7 +11,7 @@ from pipecat.services.settings import LLMSettings
 
 from services.brains.base import BrainRuntime
 from services.runtime_variables import DynamicVariableStore
-from services.vision import VISION_SYSTEM_HINT
+from services.vision import vision_system_hint
 from services.workflow_engine import WorkflowEngine
 from services.workflow_router import WorkflowLLMRouter
 
@@ -47,7 +47,10 @@ class WorkflowAgentStage:
         stage_prompt = self._engine.prompt_for(node_id, self._store)
         stage = self._engine.agent_stage_config(node_id)
         if stage.vision_enabled:
-            stage_prompt = f"{stage_prompt}\n\n[视觉能力]\n{VISION_SYSTEM_HINT}"
+            stage_prompt = (
+                f"{stage_prompt}\n\n[视觉能力]\n"
+                f"{vision_system_hint(stage.vision_focus_prompt)}"
+            )
         instruction = (
             EDGE_TOOL_STAGE_INSTRUCTION
             if self._engine.llm_routing_mode() == "edge_tool"
@@ -109,6 +112,7 @@ class WorkflowAgentStage:
                 {
                     "enabled": stage.vision_enabled,
                     "vision_model_resource_id": stage.vision_model_resource_id,
+                    "vision_focus_prompt": stage.vision_focus_prompt,
                     "llm_resource_id": stage.llm_resource_id,
                 }
             )