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/services/migrate.py

@@ -7,7 +7,8 @@ from app.core.database import engine
 def run_migrations() -> None:
     """Apply lightweight schema updates for existing databases."""
     inspector = inspect(engine)
-    if "students" not in inspector.get_table_names():
+    tables = set(inspector.get_table_names())
+    if "students" not in tables:
         return
 
     columns = {col["name"] for col in inspector.get_columns("students")}
@@ -20,7 +21,7 @@ def run_migrations() -> None:
                 )
             )
 
-    if "users" in inspector.get_table_names():
+    if "users" in tables:
         user_columns = {col["name"] for col in inspector.get_columns("users")}
         if "is_superuser" not in user_columns:
             with engine.begin() as conn:
@@ -33,3 +34,34 @@ def run_migrations() -> None:
                         f"WHERE username = '{settings.ADMIN_DEFAULT_USERNAME}'"
                     )
                 )
+
+    if "wrong_questions" in tables:
+        wq_columns = {col["name"] for col in inspector.get_columns("wrong_questions")}
+        if "category" not in wq_columns:
+            with engine.begin() as conn:
+                conn.execute(
+                    text(
+                        "ALTER TABLE wrong_questions ADD COLUMN category VARCHAR(32) "
+                        "NOT NULL DEFAULT 'regular'"
+                    )
+                )
+
+    if "system_settings" in tables:
+        ss_columns = {col["name"] for col in inspector.get_columns("system_settings")}
+        alters: list[str] = []
+        if "ai_provider" not in ss_columns:
+            alters.append("ADD COLUMN ai_provider VARCHAR(16) NOT NULL DEFAULT 'ollama'")
+        if "ollama_base_url" not in ss_columns:
+            alters.append("ADD COLUMN ollama_base_url VARCHAR(256)")
+        if "ollama_model" not in ss_columns:
+            alters.append("ADD COLUMN ollama_model VARCHAR(128)")
+        if "openai_base_url" not in ss_columns:
+            alters.append("ADD COLUMN openai_base_url VARCHAR(256)")
+        if "openai_model" not in ss_columns:
+            alters.append("ADD COLUMN openai_model VARCHAR(128)")
+        if "openai_api_key" not in ss_columns:
+            alters.append("ADD COLUMN openai_api_key VARCHAR(512)")
+        if alters:
+            with engine.begin() as conn:
+                for clause in alters:
+                    conn.execute(text(f"ALTER TABLE system_settings {clause}"))