feat: start-at-login is a Settings switch, off by default (v2.5.0)

- Settings → About → "Start AgentHub automatically" (AutostartSettings.tsx,
  GET/PUT /api/settings/autostart, server/lib/autostart.js). The switch is
  the systemd --user unit's / LaunchAgent's enabled state: on writes a unit
  for the running server when none exists and enables it, off disables it;
  neither starts or stops the server. A foreign unit is never touched
  (409 EFOREIGN)
- The plugin bootstrap no longer installs a unit on every install: it
  installs or starts one only while the user has it enabled, and a rewrite
  keeps the enabled state (writeUserService({ enable })). An install that
  already had the unit enabled stays on. A stale-but-enabled unit beside a
  live detached server is repointed, no longer started onto the bound port
- unitIsEnabled / setUnitEnabled in systemd-service.js and launchd-service.js

Also:
- fix(workspace): status bar no longer covers the chat box below md (#61)

scripts/launchd-service.js

@@ -105,6 +105,26 @@ function unitIsActive(name) {
   return res.status === 0 && /^\s*state = running$/m.test(String(res.stdout || ""));
 }
 
+/** Is our plist set to load at login — the Settings "start automatically"
+ *  switch. A `launchctl disable` override is what turns it off. */
+function unitIsEnabled(name) {
+  if (!systemctlAvailable() || !unitIsOurs(name)) return false;
+  const res = launchctl(["print-disabled", domain()]);
+  const line = String(res.stdout || "")
+    .split("\n")
+    .find((l) => l.includes(`"${jobLabel(name)}"`));
+  return !line || !/=>\s*(disabled|true)/.test(line);
+}
+
+/** Enable or disable loading at login — never loads or unloads the job, so
+ *  the server answering the switch stays up either way. */
+function setUnitEnabled(name, on) {
+  if (!systemctlAvailable()) return "unavailable";
+  if (!unitIsOurs(name)) return "foreign";
+  const res = launchctl([on ? "enable" : "disable", `${domain()}/${jobLabel(name)}`]);
+  return res.status === 0 ? "ok" : "failed";
+}
+
 /**
  * `argv` is the program and its arguments as separate strings (the systemd
  * twin's `execStart` is one line; a path with a space would split here).
@@ -153,14 +173,15 @@ ${envLines}
 }
 
 /**
- * Writes the plist and clears any "disabled" override — and starts nothing.
+ * Writes the plist and clears any "disabled" override (unless `enable:
+ * false`, which leaves it as it is) — and starts nothing.
  * A loaded job keeps running its OLD definition until `restartUserService`;
  * an unloaded one is picked up at the next login. Same split, same reason, as
  * the systemd twin.
  *
  * @returns {"written"|"unchanged"|"foreign"|"unavailable"|"failed"}
  */
-function writeUserService({ name, workingDir, argv, env = {} }) {
+function writeUserService({ name, workingDir, argv, env = {}, enable = true }) {
   if (!systemctlAvailable()) return "unavailable";
   const body = unitContent({ name, workingDir, argv, env });
   const target = unitPath(name);
@@ -173,7 +194,7 @@ function writeUserService({ name, workingDir, argv, env = {} }) {
     fs.mkdirSync(path.dirname(target), { recursive: true });
     fs.mkdirSync(path.dirname(logPath()), { recursive: true });
     fs.writeFileSync(target, body, "utf8");
-    launchctl(["enable", `${domain()}/${jobLabel(name)}`]);
+    if (enable) launchctl(["enable", `${domain()}/${jobLabel(name)}`]);
     return "written";
   } catch {
     return "failed";
@@ -229,6 +250,8 @@ module.exports = {
   unitIsStale,
   unitRoot,
   unitIsActive,
+  unitIsEnabled,
+  setUnitEnabled,
   writeUserService,
   restartUserService,
   installUserService,