fix(s03): match Windows del as a command word

s09_memory/README.ja.md

@@ -170,6 +170,10 @@ except Exception:
 
 ---
 
+## 継承する権限ルール
+
+この章は s04 の permission hook を引き継ぐ。command の先頭または shell separator（`;`、`&&`、`||`、`|`、`&`、括弧、改行）の直後にある完全な `rm`/`del` command word だけを大文字小文字を区別せず検出する。`model`、`delimiter`、`echo del test.txt` は危険な command として扱わない。
+
 ## 試してみる
 
 ```sh

s09_memory/README.md

@@ -170,6 +170,10 @@ The course uses a simple count threshold. A real application must also choose a
 
 ---
 
+## Inherited permission rule
+
+This chapter carries forward the permission hook from s04. It recognizes `rm` and `del` case-insensitively only as complete command words at the start of a command or after a shell separator (`;`, `&&`, `||`, `|`, `&`, parentheses, or a newline). It does not treat `model`, `delimiter`, or `echo del test.txt` as destructive.
+
 ## Try It
 
 ```sh

s09_memory/README.zh.md

@@ -170,6 +170,10 @@ except Exception:
 
 ---
 
+## 继承的权限规则
+
+本章沿用 s04 的权限 hook：只在命令开头或 shell 分隔符（`;`、`&&`、`||`、`|`、`&`、括号或换行）之后，按大小写不敏感方式识别完整的 `rm`/`del` 命令词。`model`、`delimiter` 和 `echo del test.txt` 不会被当成危险命令。
+
 ## 试一下
 
 ```sh

s09_memory/code.py

@@ -634,7 +634,15 @@ def trigger_hooks(event: str, *args):
     return None
 
 DENY_LIST = ["rm -rf /", "sudo", "shutdown", "reboot", "mkfs", "dd if="]
-DESTRUCTIVE = ["rm ", "> /etc/", "chmod 777"]
+DESTRUCTIVE_COMMAND_WORD = re.compile(
+    r"(?i)(?:^|[;&|()\n])\s*(?:rm|del)(?=\s|$|[;&|()])"
+)
+DESTRUCTIVE = ["> /etc/", "chmod 777"]
+
+
+def contains_destructive_command(command: str) -> bool:
+    return bool(DESTRUCTIVE_COMMAND_WORD.search(command))
+
 
 def permission_hook(block):
     if block.name == "bash":
@@ -642,7 +650,9 @@ def permission_hook(block):
         for pattern in DENY_LIST:
             if pattern in command:
                 return f"Permission denied by deny list: {pattern}"
-        if any(keyword in command for keyword in DESTRUCTIVE):
+        if contains_destructive_command(command) or any(
+            keyword in command for keyword in DESTRUCTIVE
+        ):
             print("\n\033[33m[permission] Potentially destructive command\033[0m")
             print(f"   Tool: {block.name}({block.input})")
             if input("   Allow? [y/N] ").strip().lower() not in ("y", "yes"):