refactor(cli): 重构清屏和which命令实现

1. 提取清屏、设置环境变量、命令查找逻辑到system任务模块
2. 统一命令行工具的任务实现方式，减少重复代码
3. 修正pyproject.toml中的cli命令名拼写错误
4. 移除过时的测试用例代码

src/pyflowx/cli/clearscreen.py

@@ -6,14 +6,10 @@
 from __future__ import annotations
 
 import pyflowx as px
-from pyflowx.conditions import Constants
+from pyflowx.tasks.system import CLR
 
 
 def main() -> None:
     """清屏工具主函数."""
-    graph = px.Graph.from_specs([
-        px.TaskSpec("cls_win", cmd=["cmd", "/c", "cls"], conditions=(lambda: Constants.IS_WINDOWS,)),
-        px.TaskSpec("cls_unix", cmd=["clear"], conditions=(lambda: not Constants.IS_WINDOWS,)),
-        px.TaskSpec("cls_ascii", fn=lambda: print("\033[2J\033[H", end="")),
-    ])
+    graph = px.Graph.from_specs([CLR()])
     px.run(graph, strategy="thread")

src/pyflowx/cli/which.py

@@ -6,46 +6,16 @@
 from __future__ import annotations
 
 import argparse
-import shutil
-from pathlib import Path
 
 import pyflowx as px
-
-
-def which_command(command: str) -> Path | None:
-    """查找命令路径.
-
-    Parameters
-    ----------
-    command : str
-        命令名称
-
-    Returns
-    -------
-    Path | None
-        命令路径, 如果未找到则返回 None
-    """
-    cmd_path = shutil.which(command)
-    if cmd_path:
-        print(f"匹配路径: - {cmd_path}")
-        return Path(cmd_path)
-    else:
-        print(f"{command}: 未找到")
-        return None
+from pyflowx.tasks.system import WHICH
 
 
 def main() -> None:
     """命令查找工具主函数."""
-    parser = argparse.ArgumentParser(
-        description="Which - 命令查找工具",
-        usage="which <command> [command ...]",
-    )
-    parser.add_argument(
-        "commands",
-        type=str,
-        nargs="+",
-        help="要查找的命令名称 (如: python pip node npm git uv rustc cargo)",
-    )
+    parser = argparse.ArgumentParser(description="Which - 命令查找工具")
+    parser.add_argument("commands", nargs="+", help="要查找的命令名称, 如: python ls ps gcc...")
     args = parser.parse_args()
-    graph = px.Graph.from_specs([px.TaskSpec(f"which_{cmd}", fn=which_command, args=(cmd,)) for cmd in args.commands])
+
+    graph = px.Graph.from_specs([WHICH(cmd) for cmd in args.commands])
     px.run(graph, strategy="thread")

src/pyflowx/tasks/system.py

@@ -0,0 +1,38 @@
+import pyflowx as px
+
+
+def CLR():
+    """清屏."""
+    import subprocess
+
+    from pyflowx.conditions import Constants
+
+    return px.TaskSpec(
+        "clear_screen", fn=lambda: subprocess.run(["cls"] if Constants.IS_WINDOWS else ["clear"], check=True)
+    )
+
+
+def SETENV(name: str, value: str):
+    """设置环境变量."""
+    import os
+
+    return px.TaskSpec("set_env", fn=lambda: os.environ.setdefault(name, value))
+
+
+def WHICH(cmd: str):
+    """查找命令路径."""
+    import subprocess
+
+    def find_command() -> str | None:
+        """查找命令并返回路径, 找不到时返回 None."""
+        result = subprocess.run(["which", cmd], capture_output=True, text=True, check=False)
+
+        if result.returncode == 0:
+            path = result.stdout.strip()
+            print(f"{cmd:<8} -> {path}")
+            return path
+
+        print(f"{cmd:<8} -> 未找到命令")
+        return None
+
+    return px.TaskSpec(f"which_{cmd}", fn=find_command)