移动端拍照上传、奥数区、学段约束解题与 AI 模型配置。

- 手机/平板响应式布局，支持拍照与相册上传

- 学生详情新增奥数区，按初/高中学段生成解法并禁止超纲

- 系统设置可配置 Ollama 或 OpenAI 兼容 API

- 更新 frontend/dist 与使用说明

backend/app/models/user.py

@@ -22,6 +22,16 @@ class WrongQuestionStatus(str, enum.Enum):
     failed = "failed"
 
 
+class WrongQuestionCategory(str, enum.Enum):
+    regular = "regular"
+    olympiad = "olympiad"
+
+
+class AIProvider(str, enum.Enum):
+    ollama = "ollama"
+    openai = "openai"
+
+
 class SchoolLevel(str, enum.Enum):
     junior_high = "junior_high"
     senior_high = "senior_high"
@@ -123,6 +133,9 @@ class WrongQuestion(Base):
     status: Mapped[WrongQuestionStatus] = mapped_column(
         Enum(WrongQuestionStatus), default=WrongQuestionStatus.pending
     )
+    category: Mapped[WrongQuestionCategory] = mapped_column(
+        Enum(WrongQuestionCategory), default=WrongQuestionCategory.regular
+    )
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
     )
@@ -136,6 +149,12 @@ class SystemSettings(Base):
 
     id: Mapped[int] = mapped_column(Integer, primary_key=True, default=1)
     registration_enabled: Mapped[bool] = mapped_column(default=True)
+    ai_provider: Mapped[str] = mapped_column(String(16), default="ollama")
+    ollama_base_url: Mapped[str | None] = mapped_column(String(256), nullable=True)
+    ollama_model: Mapped[str | None] = mapped_column(String(128), nullable=True)
+    openai_base_url: Mapped[str | None] = mapped_column(String(256), nullable=True)
+    openai_model: Mapped[str | None] = mapped_column(String(128), nullable=True)
+    openai_api_key: Mapped[str | None] = mapped_column(String(512), nullable=True)
     updated_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), default=lambda: datetime.now(timezone.utc)
     )