Account · Sign in: log in, sign up, providers, a link by email, a second factor

LoginForm takes an email and a password, keeps one signed in on a box,
and signs in on Enter once the address reads and a password is typed;
a failed try says why above Sign in. SignupForm ticks a new password's
rules as they hold and waits for all of them and the terms.
OAuthButtons offer each provider, one spinning while the rest rest.
MagicLinkForm and ForgotPassword send a link to an address and, once
sent, say where it went and offer it again. TwoFactorInput takes a
six-digit code at once and, after one fails, clears the boxes through
forms::PinInput's new attempt, keeping its focus. The Account chapter
splits into sign-in, profile and access, and billing and team.

TASKS.md

@@ -125,7 +125,9 @@ Per-component lines live in `tasks/`. Tags there:
 - [x] T33d DB & Dev Tools · Tools and machines — `tasks/ch31-43.md`
 - [x] T34 Dashboard — `tasks/ch31-43.md` (its two maps lines wait for T41)
 - [x] T35 Settings — `tasks/ch31-43.md`
-- [ ] T36 Account
+- [ ] T36a Account · Sign in
+- [ ] T36b Account · Profile and access
+- [ ] T36c Account · Billing and team
 - [ ] T37 Onboarding & Help
 - [ ] T38 Interaction
 - [ ] T39 Theme