chore: 收尾清账——type:module/gitattributes/engines/lint/CI/根typecheck覆盖

Co-Authored-By: Claude Code <noreply@anthropic.com>

packages/contracts/package.json

@@ -12,6 +12,7 @@
     }
   },
   "scripts": {
-    "build": "tsc -p tsconfig.json"
+    "build": "tsc -p tsconfig.json",
+    "typecheck": "tsc -p tsconfig.json --noEmit"
   }
 }

packages/contracts/src/universal-row.ts

@@ -20,6 +20,7 @@ export interface UniversalRow {
   rawLocation: string
 }
 
+// eslint-disable-next-line @typescript-eslint/no-empty-object-type -- {} extends Pick<T,K> 是检测可选键的惯用条件类型比较，非"任意非空值"类型标注
 type RequiredKeys<T> = { [K in keyof T]-?: {} extends Pick<T, K> ? never : K }[keyof T]
 
 // 契约冻结：REQUIRED = 接口必填字段全集；接口新增必填字段而列表漏改 → 编译报错