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

backend/app/routers/admin.py

@@ -18,6 +18,7 @@ from app.schemas import (
     SystemSettingsOut,
     SystemSettingsUpdate,
 )
+from app.services.url_sanitize import sanitize_http_url, sanitize_model_name
 
 router = APIRouter(prefix="/admin", tags=["admin"])
 
@@ -66,13 +67,13 @@ def update_settings(
     if data.ai_provider is not None:
         row.ai_provider = data.ai_provider.value
     if data.ollama_base_url is not None:
-        row.ollama_base_url = data.ollama_base_url or None
+        row.ollama_base_url = sanitize_http_url(data.ollama_base_url) or None
     if data.ollama_model is not None:
-        row.ollama_model = data.ollama_model or None
+        row.ollama_model = sanitize_model_name(data.ollama_model) or None
     if data.openai_base_url is not None:
-        row.openai_base_url = data.openai_base_url or None
+        row.openai_base_url = sanitize_http_url(data.openai_base_url) or None
     if data.openai_model is not None:
-        row.openai_model = data.openai_model or None
+        row.openai_model = sanitize_model_name(data.openai_model) or None
     if data.openai_api_key is not None and data.openai_api_key.strip():
         row.openai_api_key = data.openai_api_key.strip()
     if data.ocr_service_url is not None: