Remove legacy JVM-specific file system, shell, and related implementations; migrate to platform-agnostic and common main modules.

src/commonMain/kotlin/mtmc/os/shell/builtins/PauseCommand.kt

@@ -0,0 +1,15 @@
+package mtmc.os.shell.builtins
+
+import mtmc.emulator.MonTanaMiniComputer
+import mtmc.os.shell.ShellCommand
+import mtmc.tokenizer.MTMCTokenizer
+
+class PauseCommand : ShellCommand() {
+  override fun exec(tokens: MTMCTokenizer, computer: MonTanaMiniComputer) {
+    computer.pause()
+  }
+  override val help: String
+
+    get() = "pause - pauses the computer"
+}
+