ui: make ControlGroup query robust; drop legacy instruction files

selective-vpn-gui/traffic_mode_dialog.py

@@ -928,19 +928,54 @@ RU: Применяет policy-rules и проверяет health. При оши
         if p.returncode != 0:
             raise RuntimeError(f"systemd-run failed: {p.returncode}\n{out}".strip())
 
-        p2 = subprocess.run(
-            ["systemctl", "--user", "show", "-p", "ControlGroup", "--value", unit],
-            capture_output=True,
-            text=True,
-            check=False,
-        )
-        out2 = ((p2.stdout or "") + (p2.stderr or "")).strip()
-        cg = (p2.stdout or "").strip()
-        if p2.returncode != 0 or not cg:
-            raise RuntimeError(f"failed to query ControlGroup\n{out2}".strip())
+        # EN: Some apps (e.g. Chrome wrappers) can return quickly; the transient scope
+        # EN: may appear/disappear fast. Retry briefly to avoid race.
+        # RU: Некоторые приложения (например, chrome-wrapper) быстро завершаются; scope
+        # RU: может появиться/исчезнуть очень быстро. Делаем небольшой retry.
+        cg = self._control_group_for_unit_retry(unit, timeout_sec=2.0)
 
         return cg, out
 
+    def _control_group_for_unit_retry(self, unit: str, *, timeout_sec: float = 2.0) -> str:
+        u = (unit or "").strip()
+        if not u:
+            raise ValueError("empty unit")
+
+        deadline = time.time() + max(0.2, float(timeout_sec or 0))
+        last_out = ""
+        while time.time() < deadline:
+            code, out = self._systemctl_user(["show", "-p", "ControlGroup", "--value", u])
+            last_out = out or ""
+            if code == 0:
+                cg = (out or "").strip()
+                if cg:
+                    return cg
+            low = (out or "").lower()
+            if "could not be found" in low or "not found" in low or "loaded units listed" in low:
+                break
+            time.sleep(0.1)
+
+        # Provide a more actionable error for users.
+        code_s, out_s = self._systemctl_user(["status", u, "--no-pager", "--plain"])
+        status_txt = (out_s or "").strip()
+        hint = (
+            "EN: Scope unit may have exited immediately. If the app is already running, "
+            "this launch may not create a new process tree inside the scope.\n"
+            "EN: Try closing the app полностью and запуск again from here.\n"
+            "RU: Scope мог завершиться сразу. Если приложение уже запущено, повторный запуск "
+            "может не создать новый процесс внутри scope.\n"
+            "RU: Попробуй полностью закрыть приложение и запустить снова отсюда."
+        )
+        raise RuntimeError(
+            (
+                "failed to query ControlGroup\n"
+                + (last_out.strip() or "(no output)")
+                + ("\n\nstatus:\n" + status_txt if status_txt else "")
+                + "\n\n"
+                + hint
+            ).strip()
+        )
+
     def on_app_run(self) -> None:
         def work() -> None:
             cmdline = (self.ed_app_cmd.text() or "").strip()