feat: add clearhistory cmd to delete the cmd log(history)

Author: yuvii-b

src/main/java/com/mycmd/App.java

@@ -79,5 +79,6 @@ private static void registerCommands(Map<String, Command> commands) {
         commands.put("history", new HistoryCommand());
         commands.put("pwd", new PwdCommand());
         commands.put("uptime", new UptimeCommand());
+        commands.put("clearhistory", new ClearHistoryCommand());
     }
 }

src/main/java/com/mycmd/ShellContext.java

@@ -41,6 +41,10 @@ public void addToHistory(String command) {
         }
     }
 
+    public void clearHistory() {
+        commandHistory.clear();
+    }
+
     /**
      * Resolve the given path (absolute or relative) to a File using the current directory.
      * If the provided path is absolute, returns it directly; otherwise returns a File rooted at currentDir.

src/main/java/com/mycmd/commands/ClearHistoryCommand.java

@@ -0,0 +1,36 @@
+package com.mycmd.commands;
+
+import com.mycmd.Command;
+import com.mycmd.ShellContext;
+
+/**
+ * Clears the stored command history.
+ * 
+ * This command removes all previously executed commands from the shell's
+ * command history. After execution, the history list will be empty and
+ * the history command will show no previous commands.
+ * 
+ * Usage:
+ * - clearhistory : Clear all stored command history
+ * 
+ * This is useful for privacy purposes or when you want to start fresh
+ * with a clean command history. The history is cleared immediately
+ * and cannot be recovered.
+ */
+public class ClearHistoryCommand implements Command {
+    @Override
+    public void execute(String[] args, ShellContext context) {
+        context.clearHistory();
+        System.out.println("Command history cleared.");
+    }
+
+    @Override
+    public String description() {
+        return "Clear the stored command history.";
+    }
+
+    @Override
+    public String usage() {
+        return "clearhistory";
+    }
+}