Refactor antiprompt flowchart and fix indentation

Updated the antipromptinjector flowchart for improved clarity and logic. Fixed indentation in expression_selector.py to correct code structure. Removed obsolete db_migration_plan.md documentation.

src/chat/antipromptinjector/流程图.md

@@ -1,18 +1,18 @@
 ```mermaid
 flowchart TD
-    A([消息进入]) --> B{LLM反注入拦截
-    是否启动？}
-    B -- 否 --> Z([进入消息流])
-    B -- 是 --> C{黑白名单判断}
-    C -- 黑名单 --> D([丢弃消息])
-    C -- 白名单 --> Z
-    C -- 不在名单中 --> E{模式选择}
-    E -- 仅正则表达模式 --> F[正则验证] --> G{验证通过？}
-    G -- 是 --> Z
-    G -- 否 --> D
-    E -- 二次判定模式 --> H[正则验证] --> I{正则结果}
-    I -- 正常 --> Z
-    I -- 可疑 --> J[LLM二次判定] --> K{判定结果}
-    K -- 安全 --> Z
-    K -- 注入风险 --> D
-```
+    A[消息进入系统] --> B{LLM反注入是否启动?}
+    B -->|是| C{黑白名单检测}
+    B -->|否| Y
+    C -->|白名单| Y{继续进行消息处理}
+    C -->|无记录| D{是否命中规则集}
+    C -->|黑名单| X{丢弃消息}
+    D -->|否| E{是否启动LLM二次分析}
+    D -->|是| G{处理模式}
+    E -->|是| F{提交LLM处理}
+    E -->|否| Y
+    F -->|LLM判定高危| G
+    F -->|LLM判定无害| Y
+    G -->|严格模式| X
+    G -->|宽松模式| H{消息加盾}
+    H --> Y
+```   

src/chat/express/expression_selector.py

@@ -140,47 +140,47 @@ class ExpressionSelector:
                 (Expression.chat_id.in_(related_chat_ids)) & (Expression.type == "grammar")
             ))
 
-        style_exprs = [
-            {
-                "situation": expr.situation,
-                "style": expr.style,
-                "count": expr.count,
-                "last_active_time": expr.last_active_time,
-                "source_id": expr.chat_id,
-                "type": "style",
-                "create_date": expr.create_date if expr.create_date is not None else expr.last_active_time,
-            }
-            for expr in style_query.scalars()
-        ]
+            style_exprs = [
+                {
+                    "situation": expr.situation,
+                    "style": expr.style,
+                    "count": expr.count,
+                    "last_active_time": expr.last_active_time,
+                    "source_id": expr.chat_id,
+                    "type": "style",
+                    "create_date": expr.create_date if expr.create_date is not None else expr.last_active_time,
+                }
+                for expr in style_query.scalars()
+            ]
 
-        grammar_exprs = [
-            {
-                "situation": expr.situation,
-                "style": expr.style,
-                "count": expr.count,
-                "last_active_time": expr.last_active_time,
-                "source_id": expr.chat_id,
-                "type": "grammar",
-                "create_date": expr.create_date if expr.create_date is not None else expr.last_active_time,
-            }
-            for expr in grammar_query.scalars()
-        ]
+            grammar_exprs = [
+                {
+                    "situation": expr.situation,
+                    "style": expr.style,
+                    "count": expr.count,
+                    "last_active_time": expr.last_active_time,
+                    "source_id": expr.chat_id,
+                    "type": "grammar",
+                    "create_date": expr.create_date if expr.create_date is not None else expr.last_active_time,
+                }
+                for expr in grammar_query.scalars()
+            ]
 
-        style_num = int(total_num * style_percentage)
-        grammar_num = int(total_num * grammar_percentage)
-        # 按权重抽样（使用count作为权重）
-        if style_exprs:
-            style_weights = [expr.get("count", 1) for expr in style_exprs]
-            selected_style = weighted_sample(style_exprs, style_weights, style_num)
-        else:
-            selected_style = []
-        if grammar_exprs:
-            grammar_weights = [expr.get("count", 1) for expr in grammar_exprs]
-            selected_grammar = weighted_sample(grammar_exprs, grammar_weights, grammar_num)
-        else:
-            selected_grammar = []
-        
-        return selected_style, selected_grammar
+            style_num = int(total_num * style_percentage)
+            grammar_num = int(total_num * grammar_percentage)
+            # 按权重抽样（使用count作为权重）
+            if style_exprs:
+                style_weights = [expr.get("count", 1) for expr in style_exprs]
+                selected_style = weighted_sample(style_exprs, style_weights, style_num)
+            else:
+                selected_style = []
+            if grammar_exprs:
+                grammar_weights = [expr.get("count", 1) for expr in grammar_exprs]
+                selected_grammar = weighted_sample(grammar_exprs, grammar_weights, grammar_num)
+            else:
+                selected_grammar = []
+            
+            return selected_style, selected_grammar
 
     def update_expressions_count_batch(self, expressions_to_update: List[Dict[str, Any]], increment: float = 0.1):
         """对一批表达方式更新count值，按chat_id+type分组后一次性写入数据库"""