feat: 增强任务步骤注入与a11y状态表达，提升树形交互稳定性

- 打通 metadata.steps 传递链路，将任务步骤注入 agent 预测上下文

- 优化 a11y tree 线性化输出：使用中心坐标并新增 states 列（expanded/collapsed/selected 等）

- 放宽可保留节点条件，保留无文本输入类控件（edit/textfield/searchbox 等）

- 强化输出约束：单轮仅允许动作代码或 WAIT/DONE/FAIL，禁止动作与 DONE 同轮返回

- 补充 avogadro 示例步骤：展开 aromatics 并选择 benzene.cjson

mm_agents/agent.py

@@ -126,7 +126,7 @@ def linearize_accessibility_tree(accessibility_tree, platform="ubuntu"):
         raise ValueError("Invalid platform, must be 'ubuntu' or 'windows'")
 
     filtered_nodes = filter_nodes(ET.fromstring(accessibility_tree), platform)
-    linearized_accessibility_tree = ["tag\tname\ttext\tclass\tdescription\tposition (top-left x&y)\tsize (w&h)"]
+    linearized_accessibility_tree = ["tag\tname\ttext\tposition (center x&y)\tsize (w&h)\tstates"]
 
     # Linearize the accessibility tree nodes into a table format
     for node in filtered_nodes:
@@ -145,14 +145,36 @@ def linearize_accessibility_tree(accessibility_tree, platform="ubuntu"):
         else:
             text = '""'
 
+        # Compute center coordinates from top-left + size/2
+        coords_str = node.get('{{{:}}}screencoord'.format(_component_ns), "")
+        size_str = node.get('{{{:}}}size'.format(_component_ns), "")
+        if coords_str and size_str:
+            try:
+                cx, cy = coords_str.strip('()').split(', ')
+                sw, sh = size_str.strip('()').split(', ')
+                center_x = int(cx) + int(sw) // 2
+                center_y = int(cy) + int(sh) // 2
+                center_str = "({:d}, {:d})".format(center_x, center_y)
+            except (ValueError, IndexError):
+                center_str = coords_str
+        else:
+            center_str = coords_str
+
+        # Extract useful UI states (expanded/collapsed/checked/selected/focused)
+        state_flags = []
+        for state_name in ["expanded", "collapsed", "checked", "selected", "focused", "pressed"]:
+            val = node.get("{{{:}}}{:}".format(_state_ns, state_name), "")
+            if val == "true":
+                state_flags.append(state_name)
+        states_str = ",".join(state_flags) if state_flags else ""
+
         linearized_accessibility_tree.append(
-            "{:}\t{:}\t{:}\t{:}\t{:}\t{:}\t{:}".format(
+            "{:}\t{:}\t{:}\t{:}\t{:}\t{:}".format(
                 node.tag, node.get("name", ""),
                 text,
-                node.get("{{{:}}}class".format(_attributes_ns), "") if platform == "ubuntu" else node.get("{{{:}}}class".format(class_ns_windows), ""),
-                node.get("{{{:}}}description".format(_attributes_ns), ""),
-                node.get('{{{:}}}screencoord'.format(_component_ns), ""),
-                node.get('{{{:}}}size'.format(_component_ns), "")
+                center_str,
+                size_str,
+                states_str
             )
         )
 
@@ -332,11 +354,13 @@ class PromptAgent:
 
         self.system_message = self.system_message.format(CLIENT_PASSWORD=self.client_password, SCREEN_WIDTH=self.screen_width, SCREEN_HEIGHT=self.screen_height)
 
-    def predict(self, instruction: str, obs: Dict) -> List:
+    def predict(self, instruction: str, obs: Dict, metadata_steps: str = "") -> List:
         """
         Predict the next action(s) based on the current observation.
         """
         system_message = self.system_message + "\nYou are asked to complete the following task: {}".format(instruction)
+        if metadata_steps:
+            system_message += "\n\nHere are the reference steps from the software tutorial, which may help you complete the task:\n{}".format(metadata_steps)
 
         # Prepare the payload for the API call
         messages = []