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>

messages/en.json

@@ -268,6 +268,10 @@
     "no_account": "Create account",
     "or_divider": "or",
     "or_email_divider": "or sign in with email",
+    "login_new_here": "New here?",
+    "method_email_chip": "Email",
+    "show_password": "Show password",
+    "hide_password": "Hide password",
     "login_failed_title": "Sign in failed",
     "login_failed_bankid": "Could not complete BankID sign in.",
     "login_invalid_credentials": "Wrong email address or password.",

messages/sv.json

@@ -268,6 +268,10 @@
     "no_account": "Skapa konto",
     "or_divider": "eller",
     "or_email_divider": "eller logga in med e-post",
+    "login_new_here": "Ny här?",
+    "method_email_chip": "E-post",
+    "show_password": "Visa lösenord",
+    "hide_password": "Dölj lösenord",
     "login_failed_title": "Inloggning misslyckades",
     "login_failed_bankid": "Kunde inte slutföra BankID-inloggningen.",
     "login_invalid_credentials": "Fel e-postadress eller lösenord.",