清理 Ollama/API URL 中的终端控制字符，修复 AI 调用失败。

backend/app/services/llm.py

@@ -4,6 +4,7 @@ from sqlalchemy.orm import Session
 from app.core.config import settings as app_settings
 from app.models.user import SchoolLevel, SystemSettings
 from app.services.school_level import school_level_label
+from app.services.url_sanitize import sanitize_http_url, sanitize_model_name
 
 CURRICULUM_JUNIOR = """初中课程标准：代数、几何（全等/相似/勾股）、一次函数与简单二次函数、基础概率统计。
 严禁使用：高中导数、向量、解析几何、排列组合进阶、复数、微积分、大学线性代数等。"""
@@ -112,18 +113,18 @@ def load_ai_config(db: Session) -> AIConfig:
     if row is None:
         return AIConfig(
             provider="ollama",
-            ollama_base_url=app_settings.OLLAMA_BASE_URL,
-            ollama_model=app_settings.OLLAMA_MODEL,
-            openai_base_url=app_settings.OPENAI_BASE_URL,
-            openai_model=app_settings.OPENAI_MODEL,
+            ollama_base_url=sanitize_http_url(app_settings.OLLAMA_BASE_URL),
+            ollama_model=sanitize_model_name(app_settings.OLLAMA_MODEL),
+            openai_base_url=sanitize_http_url(app_settings.OPENAI_BASE_URL),
+            openai_model=sanitize_model_name(app_settings.OPENAI_MODEL),
             openai_api_key=None,
         )
     return AIConfig(
         provider=row.ai_provider or "ollama",
-        ollama_base_url=row.ollama_base_url or app_settings.OLLAMA_BASE_URL,
-        ollama_model=row.ollama_model or app_settings.OLLAMA_MODEL,
-        openai_base_url=row.openai_base_url or app_settings.OPENAI_BASE_URL,
-        openai_model=row.openai_model or app_settings.OPENAI_MODEL,
+        ollama_base_url=sanitize_http_url(row.ollama_base_url or app_settings.OLLAMA_BASE_URL),
+        ollama_model=sanitize_model_name(row.ollama_model or app_settings.OLLAMA_MODEL),
+        openai_base_url=sanitize_http_url(row.openai_base_url or app_settings.OPENAI_BASE_URL),
+        openai_model=sanitize_model_name(row.openai_model or app_settings.OPENAI_MODEL),
         openai_api_key=row.openai_api_key,
     )