polish(ui): loading feedback on sync/refresh buttons system-wide (#1156)

The "Synka bank nu" row in the transactions Importera split button fired
syncAll() with zero visual feedback. SplitButton now takes busy/busyLabel
per option: the primary face and the menu row swap to a spinning Loader2,
show the busy label and go inert until the action resolves. useBankSync
holds isBusy across the whole syncAll loop so the spinner does not
flicker between per-connection syncs.

Sweep of the rest of the system for async buttons missing the same
feedback (convention: disabled + Loader2 animate-spin + label swap):

- bokslut DigitalInlamning "Uppdatera status" (Bolagsverket poll): had no
  feedback at all; now disabled + spinner + "Uppdaterar ..." while polling
- Stripe settings "Synka nu": had disabled + label swap but a static icon
- Skatteverket "Verifiera": had disabled + label swap but no spinner
- AgentMemoryPanel "Dolj"/"Aterstall" row actions: static icons on async
  patch; now swap to spinner for the busy row

Checked and intentionally unchanged: Arcim migration "Synka igen" and
"Ateranslut" (the whole step flips to a spinner view synchronously on
click), skattekonto "Forsok igen" (page flips to loading view), AgentChat
"Generera om" (streaming indicator is the feedback).

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

extensions/general/stripe/components/StripeSettingsPanel.tsx

@@ -11,7 +11,7 @@ import { Skeleton } from '@/components/ui/skeleton'
 import { useToast } from '@/components/ui/use-toast'
 import { useFormat } from '@/lib/hooks/use-format'
 import { formatCurrency, formatDate } from '@/lib/utils'
-import { CreditCard, Link2, RefreshCw, Unlink } from 'lucide-react'
+import { CreditCard, Link2, Loader2, RefreshCw, Unlink } from 'lucide-react'
 import type { StripeReviewEvent, StripeStatusResponse } from '../types'
 
 type ConnectionInfo = NonNullable<StripeStatusResponse['connection']>
@@ -302,7 +302,11 @@ export default function StripeSettingsPanel() {
               ) : (
                 <div className="flex items-center gap-2">
                   <Button variant="outline" size="sm" onClick={handleSyncNow} disabled={syncing}>
-                    <RefreshCw className="mr-2 h-4 w-4" />
+                    {syncing ? (
+                      <Loader2 className="mr-2 h-4 w-4 animate-spin" />
+                    ) : (
+                      <RefreshCw className="mr-2 h-4 w-4" />
+                    )}
                     {syncing ? t('syncing') : t('sync_now')}
                   </Button>
                   <Button variant="outline" size="sm" onClick={() => setConfirmDisconnect(true)}>