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)

client/src/pages/__tests__/__snapshots__/screens.snapshot.test.tsx.snap

@@ -7109,6 +7109,58 @@ exports[`screen snapshots > Settings — about 1`] = `
       class="scroll-mt-24"
       id="about"
     >
+      <div
+        class="mb-4"
+      >
+        <section
+          class="card p-5 scroll-mt-24"
+          id="autostart"
+        >
+          <h3
+            class="text-sm font-semibold text-fg-primary"
+          >
+            Startup
+          </h3>
+          <div
+            class="mt-2"
+          >
+            <div
+              class="flex justify-between gap-4 border-b border-border/60 last:border-b-0 py-3 items-center"
+            >
+              <div
+                class="min-w-0"
+              >
+                <p
+                  class="text-sm text-fg-secondary"
+                >
+                  Start AgentHub automatically
+                </p>
+                <p
+                  class="mt-0.5 text-xs text-fg-muted"
+                >
+                  Run the dashboard as a systemd --user service, so it starts at boot without Claude Code being opened. Turning it off keeps the running server up.
+                </p>
+              </div>
+              <div
+                class="shrink-0"
+              >
+                <button
+                  aria-checked="false"
+                  aria-label="Start AgentHub automatically"
+                  class="relative inline-flex h-5 w-9 shrink-0 items-center rounded-full transition-colors focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-accent focus-visible:ring-offset-1 focus-visible:ring-offset-surface-0 disabled:cursor-not-allowed disabled:opacity-50 bg-border-light ring-1 ring-inset ring-fg-muted/80"
+                  role="switch"
+                  type="button"
+                >
+                  <span
+                    aria-hidden="true"
+                    class="inline-block h-4 w-4 rounded-full bg-white shadow transition-transform translate-x-0.5"
+                  />
+                </button>
+              </div>
+            </div>
+          </div>
+        </section>
+      </div>
       <p
         class="text-xs text-fg-muted mb-4"
       >
@@ -7181,7 +7233,7 @@ exports[`screen snapshots > Settings — about 1`] = `
             <p
               class="text-[10px] text-status-warning/90 mt-1"
             >
-              UI build v2.4.0 (rebuild client to match)
+              UI build v2.5.0 (rebuild client to match)
             </p>
           </div>
           <div

client/src/pages/__tests__/screens.snapshot.test.tsx

@@ -334,6 +334,10 @@ vi.mock("../../lib/api", async (importOriginal) => {
           rotate: r({ token: "t", enabled: true, env_owned: false }),
           revoke: r({ enabled: false, env_owned: false }),
         },
+        autostart: {
+          get: r({ available: true, kind: "systemd", enabled: false, foreign: false }),
+          set: r({ available: true, kind: "systemd", enabled: true, foreign: false }),
+        },
         privacy: {
           get: r({
             redact_secrets: false,