[client/ui-wails] Make /update page faithful to the legacy auto-update dialog

Adds the missing info line ("Your client version is older than the
auto-update version set in Management. Updating client to: <version>.")
and replaces the spinner with the legacy 1-second dot animation
(Updating./.../...). Terminal-state wording now matches the Fyne UI
exactly: 15 min timeout, canceled, and "Update failed: <err>".

Ports mapInstallError from client/ui/update.go so daemon errors that
embed "deadline exceeded" / "canceled" hit the right branch instead of
falling through as a generic failure.

Detects the daemon dropping mid-upgrade (the legacy success signal):
if GetInstallerResult fails for 5s straight, call the new Update.Quit
service method to exit, mirroring app.Quit() in showInstallerResult.

client/ui-wails/services/update.go

@@ -4,6 +4,9 @@ package services
 
 import (
 	"context"
+	"time"
+
+	"github.com/wailsapp/wails/v3/pkg/application"
 
 	"github.com/netbirdio/netbird/client/proto"
 )
@@ -24,6 +27,18 @@ func NewUpdate(conn DaemonConn) *Update {
 	return &Update{conn: conn}
 }
 
+// Quit asks the host application to exit. The /update page calls this once
+// the daemon-side installer has reported success, mirroring the legacy
+// Fyne UI's app.Quit() in showInstallerResult. Schedules the actual exit
+// off the calling goroutine so the JS-side caller's response can return
+// before the runtime tears down.
+func (s *Update) Quit() {
+	go func() {
+		time.Sleep(100 * time.Millisecond)
+		application.Get().Quit()
+	}()
+}
+
 func (s *Update) Trigger(ctx context.Context) (UpdateResult, error) {
 	cli, err := s.conn.Client()
 	if err != nil {