feat: 实现完整的人工审核功能与子图模块

- 新增三个核心子图：人工审核、意图理解、格式化输出
- 实现完整的审核 API 端点（/api/review/*）
- 前端添加审核确认界面（右下角固定框）
- 为每个子图创建分步测试代码
- 添加功能实现文档

backend/app/agent_subgraphs/common/__init__.py

@@ -0,0 +1,60 @@
+"""
+公共工具模块
+提供可复用的基础组件
+
+导出：
+- formatter: 格式化输出工具
+- intent: 意图理解工具
+- human_review: 人工审核工具
+"""
+
+from .formatter import (
+    MarkdownFormatter,
+    TemplateManager,
+    OutputRenderer,
+    PresetTemplates
+)
+
+from .intent import (
+    IntentType,
+    Intent,
+    Entity,
+    IntentParser,
+    RuleBasedIntentClassifier,
+    RuleBasedEntityExtractor,
+    IntentRegistry,
+    create_default_intent_parser
+)
+
+from .human_review import (
+    ReviewStatus,
+    HumanReview,
+    HumanReviewStore,
+    InMemoryReviewStore,
+    HumanReviewNode,
+    ReviewManager
+)
+
+__all__ = [
+    # formatter
+    "MarkdownFormatter",
+    "TemplateManager",
+    "OutputRenderer",
+    "PresetTemplates",
+    # intent
+    "IntentType",
+    "Intent",
+    "Entity",
+    "IntentParser",
+    "RuleBasedIntentClassifier",
+    "RuleBasedEntityExtractor",
+    "IntentRegistry",
+    "create_default_intent_parser",
+    # human_review
+    "ReviewStatus",
+    "HumanReview",
+    "HumanReviewStore",
+    "InMemoryReviewStore",
+    "HumanReviewNode",
+    "ReviewManager"
+]