chore: finalize backend feature scope

app/schemas/session.py

@@ -1,4 +1,4 @@
-from pydantic import BaseModel, Field, field_validator
+from pydantic import BaseModel, Field
 
 from app.schemas.training_config import PatientConfig
 
@@ -8,16 +8,10 @@ class CreateSessionRequest(BaseModel):
 
     case_id: int
     training_type: str = Field(pattern="^(case_analysis|diagnosis_treatment|consultation)$")
-    mode: str = Field(pattern="^(novice|practice|teaching)$")
+    mode: str = Field(pattern="^practice$")
     score_type: str = Field(default="percentage", pattern="^(percentage|five_point)$")
     patient_config: PatientConfig | None = None
 
-    @field_validator("mode")
-    @classmethod
-    def normalize_mode(cls, value: str) -> str:
-        """训练模式：兼容旧 novice 请求，实际按 practice 练习模式处理。"""
-        return "practice" if value == "novice" else value
-
 
 class CreateSessionResponse(BaseModel):
     """创建会话响应：返回会话标识和 AI 病人开场白。"""
@@ -35,15 +29,6 @@ class ChatRequest(BaseModel):
     message: str = Field(min_length=1, max_length=2000)
 
 
-class ChatResponse(BaseModel):
-    """问诊消息响应：返回 AI 病人的非流式回复。"""
-
-    reply: str
-    latency_ms: int
-    model: str
-    fallback_used: bool = False
-
-
 class OrderItemResponse(BaseModel):
     """可申请检查项：只返回名称和类型，不返回结果。"""
 
@@ -116,7 +101,7 @@ class SubmitTreatmentResponse(BaseModel):
 
 
 class HintRequest(BaseModel):
-    """会话提示入参：基于当前会话上下文生成新手模式提醒。"""
+    """会话提示入参：基于当前会话上下文生成练习提示。"""
 
     last_user_message: str | None = Field(default=None, max_length=2000)
     scope: str = Field(default="current_conversation", pattern="^current_conversation$")