feat(desktop): stop the daemon when you quit the app (#2454)

Quitting the desktop app now shuts down the daemon it started, so
"restart the app" is a complete reset users can act on without first
learning what a daemon is. The old default kept it alive; the toggle
under Settings > Host still opts back in.

Existing installs already persisted `keepRunningAfterQuit: true` from
the old default, so a new default alone would only reach fresh installs.
A one-time migration resets it, and an explicit toggle afterwards
persists the migration flag and is never overridden again.

Only a desktop-managed daemon is stopped — one started with
`paseo daemon start` is left alone.

packages/desktop/src/daemon/quit-lifecycle.test.ts

@@ -7,12 +7,12 @@ import {
   stopDesktopManagedDaemonOnQuitIfNeeded,
 } from "./quit-lifecycle";
 
-const SETTINGS_KEEP_RUNNING = DEFAULT_DESKTOP_SETTINGS;
-const SETTINGS_STOP_ON_QUIT = {
+const SETTINGS_STOP_ON_QUIT = DEFAULT_DESKTOP_SETTINGS;
+const SETTINGS_KEEP_RUNNING = {
   ...DEFAULT_DESKTOP_SETTINGS,
   daemon: {
     ...DEFAULT_DESKTOP_SETTINGS.daemon,
-    keepRunningAfterQuit: false,
+    keepRunningAfterQuit: true,
   },
 };
 
@@ -29,7 +29,7 @@ function waitForQuitLifecycle(): Promise<void> {
 }
 
 describe("quit-lifecycle", () => {
-  it("only stops when keepRunningAfterQuit is explicitly disabled", () => {
+  it("stops by default and only keeps running when keepRunningAfterQuit is enabled", () => {
     expect(shouldStopDesktopManagedDaemonOnQuit(SETTINGS_STOP_ON_QUIT)).toBe(true);
     expect(shouldStopDesktopManagedDaemonOnQuit(SETTINGS_KEEP_RUNNING)).toBe(false);
   });