refactor: 简化模型管理，移除启用/禁用，优化测试和布局

- 移除供应商/模型启用禁用能力，清理DB schema/migration/API/前端
- 供应商测试改为Base URL连通性+/models探测
- 新增POST /api/models/test模型连接测试
- 新增GET /api/providers/options专用供应商选项接口
- 统一工具栏为ModelsToolbar，参考项目管理布局
- 模型弹窗优化：默认能力、响应式3列标签、并排数值
- 前后端正整数校验、供应商下拉loading/error/empty状态
- 表格列宽统一，操作列/名称列固定宽度

src/server/routes/models/create.ts

@@ -38,6 +38,12 @@ export async function handleCreateModel(req: Request, db: Database, mode: Runtim
     return jsonResponse(createApiError(`Invalid capabilities: ${invalidCaps.join(", ")}`, 400), { mode, status: 400 });
   }
 
+  const numberError = validateOptionalPositiveInteger("contextLength", body.contextLength);
+  if (numberError) return jsonResponse(createApiError(numberError, 400), { mode, status: 400 });
+
+  const tokenError = validateOptionalPositiveInteger("maxOutputTokens", body.maxOutputTokens);
+  if (tokenError) return jsonResponse(createApiError(tokenError, 400), { mode, status: 400 });
+
   const result = createModel(db, body);
   if ("error" in result) {
     return jsonResponse(createApiError(result.error, result.status), { mode, status: result.status });
@@ -45,3 +51,9 @@ export async function handleCreateModel(req: Request, db: Database, mode: Runtim
 
   return jsonResponse(result, { mode, status: 201 });
 }
+
+function validateOptionalPositiveInteger(field: string, value: null | number | undefined): null | string {
+  if (value === undefined || value === null) return null;
+  if (!Number.isInteger(value) || value <= 0) return `${field} must be a positive integer`;
+  return null;
+}