feat: 完善词典子图，添加API调用和前端格式化工具

- 完善词典子图：添加生词本功能
- 创建API调用工具：dictionary_api
- 添加前端格式化展示工具：result_formatter.py
- 创建通讯录和资讯子图的基本结构
- 更新主图状态结构，添加MainGraphState
- 添加subgraph_builder.py用于子图集成

backend/app/agent_subgraphs/contact/graph.py

@@ -0,0 +1,86 @@
+"""
+通讯录子图构建器
+Contact Subgraph Builder
+"""
+
+from langgraph.graph import StateGraph, START, END
+
+from .state import ContactState
+from .nodes import (
+    parse_intent,
+    list_contacts,
+    add_contact,
+    list_emails,
+    generate_email_draft,
+    human_review,
+    send_email,
+    sniff_contacts,
+    format_result,
+    should_continue
+)
+
+
+def build_contact_subgraph() -> StateGraph:
+    """
+    构建通讯录子图
+    
+    Returns:
+        配置好的 StateGraph
+    """
+    # 创建图
+    graph = StateGraph(ContactState)
+    
+    # 添加节点
+    graph.add_node("parse_intent", parse_intent)
+    graph.add_node("list_contacts", list_contacts)
+    graph.add_node("add_contact", add_contact)
+    graph.add_node("list_emails", list_emails)
+    graph.add_node("generate_email_draft", generate_email_draft)
+    graph.add_node("human_review", human_review)
+    graph.add_node("send_email", send_email)
+    graph.add_node("sniff_contacts", sniff_contacts)
+    graph.add_node("format_result", format_result)
+    
+    # 添加边
+    # 从START开始
+    graph.add_edge(START, "parse_intent")
+    
+    # 从parse_intent根据条件路由
+    graph.add_conditional_edges(
+        "parse_intent",
+        should_continue,
+        {
+            "list_contacts": "list_contacts",
+            "add_contact": "add_contact",
+            "list_emails": "list_emails",
+            "generate_email_draft": "generate_email_draft",
+            "sniff_contacts": "sniff_contacts",
+        }
+    )
+    
+    # 从各个操作节点到format_result
+    graph.add_edge("list_contacts", "format_result")
+    graph.add_edge("add_contact", "format_result")
+    graph.add_edge("list_emails", "format_result")
+    graph.add_edge("sniff_contacts", "format_result")
+    
+    # 邮件发送的特殊流程
+    graph.add_edge("generate_email_draft", "human_review")
+    
+    # 从human_review根据条件路由
+    graph.add_conditional_edges(
+        "human_review",
+        should_continue,
+        {
+            "send_email": "send_email",
+            "format_result": "format_result",
+        }
+    )
+    
+    # 发送邮件后到格式化
+    graph.add_edge("send_email", "format_result")
+    
+    # 最终到END
+    graph.add_edge("format_result", END)
+    
+    return graph