fix: v2.7.3 — Update now restarts through our own service unit, member panes stay live on a dev server, a start refuses a missing folder

- self-restart: a server in our unit's cgroup (/agenthub.service, system
  or user) restarts via `systemctl restart --no-block` (sudo -n for the
  system unit), our launchd job by exiting into KeepAlive. The detached
  restart-helper replacement held the port while Restart=always started
  the unit every 3 s (v2.7.2 on the S3 box: 240+ restarts, MainPID 0).
- run-as.mayHaveTmux: only ENOENT means "no tmux". A dev server in server
  mode without CAP_DAC_READ_SEARCH got EACCES on a member's 0700
  .agenthub/tmux, dropped the member from the list and ended their runs
  within seconds — the real cause of `401 not a live pane's token`.
- tmux: a member's list is re-asked every 5 s, not 1 s (one sudo + three
  auth.log lines each).
- POST /api/lanes/:id/start: 409 ENOCWD for a folder that no longer
  exists (the pane started in the account's home otherwise).
- Settings: Remote sources only for staff (a developer got a 403).
- scripts/test-server.js drops every inherited AGENTHUB_* (pane env).
Tests: self-restart.test.js, server-s3-panes (mayHaveTmux), lanes-api
(ENOCWD); touched suites 771 + client pages 191, tsc -b.

server/lib/self-restart.js

@@ -7,26 +7,85 @@
  * it, and hands the "wait for the old PID to actually die, then spawn the
  * replacement" job to a detached helper script — the dying process can't do
  * that itself without racing its own replacement for the port.
+ *
+ * A server our service unit runs (systemd `agenthub.service`, system or user;
+ * the launchd job) is restarted BY that manager instead: a detached
+ * replacement would hold the port while `Restart=always` starts the unit
+ * again every few seconds, each start exiting "already running" — forever.
  * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
  */
 
+const fs = require("fs");
 const path = require("path");
 const { spawn } = require("child_process");
 
+const UNIT = "agenthub";
+
+/**
+ * "systemd" when this process lives in our unit's cgroup, "launchd" when it
+ * is our LaunchAgent job, else null. Pure reads: no process is spawned.
+ */
+function owningUnit({
+  platform = process.platform,
+  cgroup = () => fs.readFileSync("/proc/self/cgroup", "utf8"),
+  env = process.env,
+} = {}) {
+  if (platform === "darwin") {
+    return env.XPC_SERVICE_NAME === `io.smartgift.${UNIT}` ? "launchd" : null;
+  }
+  try {
+    return cgroup()
+      .split("\n")
+      .some((l) => l.trim().endsWith(`/${UNIT}.service`))
+      ? "systemd"
+      : null;
+  } catch {
+    return null;
+  }
+}
+
 /**
  * @param {string} [root] repo root the helper should run from.
+ * @returns {"service"|"exit"|"helper"} how the restart was handed over.
  */
-function scheduleRestart(root = path.join(__dirname, "..", "..")) {
+function scheduleRestart(root = path.join(__dirname, "..", ".."), deps = {}) {
+  const {
+    unit = owningUnit(),
+    svc = () => require("../../scripts/service-manager"),
+    kill = () => process.kill(process.pid, "SIGTERM"),
+    spawnHelper = spawn,
+  } = deps;
+  // systemd: one non-blocking restart job (sudo -n for the system unit). If
+  // that cannot be asked, a plain exit still comes back — the unit is
+  // Restart=always — but never with a second server beside it.
+  if (unit === "systemd") {
+    let restarted = false;
+    try {
+      restarted = svc().restartUserService(UNIT) === "restarted";
+    } catch {
+      /* fall through to the exit */
+    }
+    if (restarted) return "service";
+    kill();
+    return "exit";
+  }
+  // launchd: KeepAlive restarts the job on exit; a `bootout` from inside the
+  // job would wait for this very process.
+  if (unit === "launchd") {
+    kill();
+    return "exit";
+  }
   const helperPath = path.join(root, "scripts", "restart-helper.js");
   const entry = process.argv[1] || path.join(root, "server", "index.js");
-  const helper = spawn(process.execPath, [helperPath, String(process.pid), entry], {
+  const helper = spawnHelper(process.execPath, [helperPath, String(process.pid), entry], {
     cwd: root,
     detached: true,
     stdio: "ignore",
     env: process.env,
   });
   helper.unref();
-  process.kill(process.pid, "SIGTERM");
+  kill();
+  return "helper";
 }
 
-module.exports = { scheduleRestart };
+module.exports = { scheduleRestart, owningUnit };