refactor: 全面迁移至 Python 3.9+ 原生泛型类型语法

- 将所有 `Optional[T]` 替换为 `T | None`
- 将所有 `List[T]`/`Dict[K, V]`/`Tuple[Ts, ...]` 替换为对应原生泛型
- 调整类型导入，移除冗余的 typing 导入项
- 更新项目依赖，添加 typing-extensions 兼容旧版本 Python
- 重构部分函数签名与内部实现以匹配新类型语法

uv.lock

@@ -1907,6 +1907,8 @@ version = "0.1.2"
 source = { editable = "." }
 dependencies = [
     { name = "graphlib-backport", marker = "python_full_version < '3.9'" },
+    { name = "typing-extensions", version = "4.13.2", source = { registry = "https://mirrors.aliyun.com/pypi/simple/" }, marker = "python_full_version < '3.9'" },
+    { name = "typing-extensions", version = "4.15.0", source = { registry = "https://mirrors.aliyun.com/pypi/simple/" }, marker = "python_full_version >= '3.9'" },
 ]
 
 [package.optional-dependencies]
@@ -1961,6 +1963,7 @@ requires-dist = [
     { name = "ruff", marker = "extra == 'dev'", specifier = ">=0.8.0" },
     { name = "tox", marker = "extra == 'dev'", specifier = ">=4.25.0" },
     { name = "tox-uv", marker = "extra == 'dev'", specifier = ">=1.13.1" },
+    { name = "typing-extensions", specifier = ">=4.13.2" },
 ]
 provides-extras = ["dev"]
 
@@ -2759,6 +2762,7 @@ name = "typing-extensions"
 version = "4.15.0"
 source = { registry = "https://mirrors.aliyun.com/pypi/simple/" }
 resolution-markers = [
+    "python_full_version >= '3.15'",
     "python_full_version >= '3.10' and python_full_version < '3.15'",
     "python_full_version > '3.9' and python_full_version < '3.10'",
     "python_full_version == '3.9'",