feat: add placeholder cmdline concept

wfassoc/tests/concept.rs

@@ -276,3 +276,26 @@ fn test_verb() {
 }
 
 // endregion
+
+// region: Command Line
+
+#[test]
+fn test_cmd_line() {
+    fn ok_tester(s: &str) {
+        let rv = CmdLine::from_str(s);
+        assert!(rv.is_ok());
+        // let rv = rv.unwrap();
+        // assert_eq!(s, rv.full());
+    }
+    fn err_tester(s: &str) {
+        let rv = CmdLine::from_str(s);
+        assert!(rv.is_err());
+    }
+
+    ok_tester("notepad.exe");
+    ok_tester("calc.exe /c");
+    ok_tester("unix-like.exe -i some.file --option");
+    // err_tester("");
+}
+
+// endregion