feat(login): method-state login panel with quiet inline errors (#1469)

* feat(login): method-state login panel with quiet inline errors

The login panel now shows one method at a time (the pattern Swedish
users know from banks, Kivra and Fortnox): BankID as the hero state,
the email form as a peer state, and the remaining methods as two quiet
half-width chips under a single divider. The last successful method is
remembered in an accounted-login-method cookie, read server-side so a
returning password user gets the form on the first paint with no flash.

Error display drops the boxed banner everywhere: credential failures
render as one destructive sentence directly under the password field
(fields keep aria-invalid), and the reset-password action surfaces from
the second consecutive failure. BankID/Google failures, callback errors
and the session-timeout notice are single quiet lines at the top of the
panel (AttnLine for the informational one).

Also: password visibility toggle, webkit autofill repaint to the theme
surface, auth pages move from the gradient background to the app frame
tone, register/MFA/reset get the same backdrop for cross-page
coherence, and Skapa konto moves out of the panel into a footer line.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

* feat(register): mirror the method-state panel on signup

Same treatment as the login page: BankID signup as the hero state, the
email form as a peer state (live password checklist kept), alternatives
as half-width chips under one divider, quiet-line notices instead of
the blue box, subtitle dropped, footer harmonized. Successful signup
persists the method hint so the user's first login opens correctly.
The BankID-verified email-collection step keeps its panel takeover.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

---------

Co-authored-by: Jakob Wennberg <311770904+jakobwennberg-oss@users.noreply.github.com>
Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

components/auth/AuthFormError.tsx

@@ -1,14 +1,17 @@
 'use client'
 
 import type { ReactNode } from 'react'
+import { CircleAlert } from 'lucide-react'
 
 /**
- * Inline error alert for the auth forms (login, register, reset).
+ * Inline error line for the auth forms (login, register, reset).
  *
- * Auth failures render here, adjacent to the fields, instead of in a toast:
+ * Auth failures render here, adjacent to the form, instead of in a toast:
  * a toast in the corner auto-dismisses, sits far from the locus of attention,
- * and is easy to miss entirely. role="alert" makes screen readers announce
- * the message when it appears.
+ * and is easy to miss entirely. Styled as one quiet destructive sentence with
+ * an icon, mirroring the AttnLine pattern, never as a boxed banner: the box
+ * reads louder than the message and breaks the panel's rhythm. role="alert"
+ * makes screen readers announce the message when it appears.
  */
 export function AuthFormError({
   message,
@@ -18,14 +21,15 @@ export function AuthFormError({
   action?: ReactNode
 }) {
   return (
-    <div
+    <p
       role="alert"
-      className="animate-fade-in rounded-lg border border-destructive/30 bg-destructive/5 p-4"
+      className="animate-fade-in flex items-start gap-2 text-[13px] leading-5 text-destructive"
     >
-      <p className="text-sm text-destructive">
+      <CircleAlert className="mt-0.5 h-3.5 w-3.5 shrink-0" aria-hidden="true" />
+      <span>
         {message}
         {action && <> {action}</>}
-      </p>
-    </div>
+      </span>
+    </p>
   )
 }