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/dictionary/graph.py

@@ -0,0 +1,71 @@
+"""
+词典子图构建器 - 完善版
+Dictionary Subgraph Builder - Complete
+"""
+
+from langgraph.graph import StateGraph, START, END
+
+from .state import DictionaryState
+from .nodes import (
+    parse_intent,
+    query_word,
+    translate_text,
+    extract_terms,
+    get_daily_word,
+    lookup_word_book,
+    add_to_word_book,
+    format_result,
+    should_continue
+)
+
+
+def build_dictionary_subgraph() -> StateGraph:
+    """
+    构建词典子图
+    
+    Returns:
+        配置好的 StateGraph
+    """
+    # 创建图
+    graph = StateGraph(DictionaryState)
+    
+    # 添加节点
+    graph.add_node("parse_intent", parse_intent)
+    graph.add_node("query_word", query_word)
+    graph.add_node("translate_text", translate_text)
+    graph.add_node("extract_terms", extract_terms)
+    graph.add_node("get_daily_word", get_daily_word)
+    graph.add_node("lookup_word_book", lookup_word_book)
+    graph.add_node("add_to_word_book", add_to_word_book)
+    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,
+        {
+            "query_word": "query_word",
+            "translate_text": "translate_text",
+            "extract_terms": "extract_terms",
+            "get_daily_word": "get_daily_word",
+            "lookup_word_book": "lookup_word_book",
+            "add_to_word_book": "add_to_word_book",
+        }
+    )
+    
+    # 从各个操作节点到format_result
+    graph.add_edge("query_word", "format_result")
+    graph.add_edge("translate_text", "format_result")
+    graph.add_edge("extract_terms", "format_result")
+    graph.add_edge("get_daily_word", "format_result")
+    graph.add_edge("lookup_word_book", "format_result")
+    graph.add_edge("add_to_word_book", "format_result")
+    
+    # 最终到END
+    graph.add_edge("format_result", END)
+    
+    return graph