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)

server/openapi-extra/misc.js

@@ -4,6 +4,8 @@
  *   - GET    /api/sessions/facets              (Sessions)
  *   - GET    /api/settings/claude-home         (Settings)
  *   - PUT    /api/settings/claude-home         (Settings)
+ *   - GET    /api/settings/autostart           (Settings)
+ *   - PUT    /api/settings/autostart           (Settings)
  *   - GET    /api/workflows/runs               (Workflows)
  *   - GET    /api/workflows/runs/{runId}       (Workflows)
  *   - GET    /api/remote-sources               (Remote Sources)
@@ -1009,6 +1011,70 @@ const paths = {
     },
   },
 
+  "/api/settings/autostart": (() => {
+    const status = {
+      description: "Start-at-login state",
+      content: {
+        "application/json": {
+          schema: {
+            type: "object",
+            required: ["available", "kind", "enabled", "foreign"],
+            properties: {
+              available: {
+                type: "boolean",
+                description: "False with no systemd --user (Linux) or GUI login (macOS)",
+              },
+              kind: { type: "string", enum: ["systemd", "launchd"] },
+              enabled: { type: "boolean" },
+              foreign: {
+                type: "boolean",
+                description: "A unit named agenthub exists that AgentHub did not write",
+              },
+            },
+          },
+        },
+      },
+    };
+    return {
+      get: {
+        tags: ["Settings"],
+        summary: "Whether the dashboard starts at boot/login",
+        description:
+          "The per-user service's enabled state (a systemd `--user` unit, or a LaunchAgent on macOS). Off by default.",
+        operationId: "getAutostart",
+        responses: { 200: status },
+      },
+      put: {
+        tags: ["Settings"],
+        summary: "Turn start-at-login on or off",
+        description:
+          "Enables or disables the unit, writing one for the running server first when none exists. Never starts or stops the server. Same-origin only.",
+        operationId: "setAutostart",
+        requestBody: {
+          required: true,
+          content: {
+            "application/json": {
+              schema: {
+                type: "object",
+                required: ["enabled"],
+                properties: { enabled: { type: "boolean" } },
+              },
+            },
+          },
+        },
+        responses: {
+          200: { ...status, description: "The new state" },
+          400: {
+            description:
+              "EBADVALUE: `enabled` is not a boolean; EUNAVAILABLE: no systemd --user / launchd GUI session",
+          },
+          403: { description: "EBADORIGIN: another site asked" },
+          409: { description: "EFOREIGN: a unit named agenthub that AgentHub did not write" },
+        },
+      },
+    };
+  })(),
+
   "/api/settings/codex-hooks": (() => {
     const status = {
       description: "Where AgentHub's Codex hooks stand",