feat(web): full auth screens rework to match design + old-app business rules

Rebuilt tenant/login/register/reset-password to match the design handoff's
01-account screens precisely (previously only loosely approximated), and
ported the old app's real business rules instead of guessing:

- LoginPage: desktop split branding panel (>=900px), terms-agreement
  checkbox gating submit, forgot-password link, password visibility toggle,
  full ctrl-error translation table (lib/tinode/errors.ts, ported from the
  old app's CTRL_ERROR_TEXT_CN/translateCtrlError -- registration/login go
  over native WS, not REST, so client.ts's REASON_MESSAGES never applied).
- RegisterPage: rebuilt as the real unified username-OR-phone form (not
  phone-only) -- username optional unless phone is blank, invite code
  required+validated only on the username-only path, matching the server's
  actual resolveRegistrationAccount rules. connection.ts's
  registerAccountByPhone generalized into registerAccount() supporting both
  paths, including the Tinode.credential(null) crash the old app had to
  work around on the username-only path.
- New ResetPasswordPage wired to /auth/password-reset/* (a different
  endpoint family than registration's /auth/verification-codes/*).
- Shared components: PasswordInput, VerificationCodeButton, Agreement,
  Toast.
- Fixed tinode-sdk.d.ts: the real method is getCurrentUserID(), not the
  invented getAuthenticatedUserID() -- caught live, login crashed past a
  successful auth.
- Fixed a responsive bug present on all four auth pages: fixed w-[380px]
  forms overflowed past the viewport edge below ~430px wide.

Verified end-to-end against the real backend (api.118im.com, tenant
"default"): fresh phone registration, password reset, re-login with the
new password, and the username-only path's invite-code rejection all
round-tripped correctly.

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

web/src/features/auth/TenantEntryPage.tsx

@@ -31,8 +31,8 @@ export function TenantEntryPage() {
   };
 
   return (
-    <div className="flex h-dvh w-full items-center justify-center bg-surface-page">
-      <form onSubmit={submit} className="flex w-[380px] flex-col gap-5">
+    <div className="flex h-dvh w-full items-center justify-center bg-surface-page px-6">
+      <form onSubmit={submit} className="flex w-full max-w-[380px] flex-col gap-5">
         <div className="mb-2 flex flex-col items-center gap-3">
           <div className="grid h-[72px] w-[72px] place-items-center rounded-2xl bg-accent text-3xl font-bold text-white">
             M