password-reset: a confirmed e-mail, then a link to reset the password

Agreed by the owner on 2026-10-13 ("the e-mail must be confirmed");
notifications to an unconfirmed address settled on 2026-10-17: "Без
подтверждения слать". Mockups 2f5f5b2, route guard b7bbb2c, panel guard
0774da2.

Migration 0013: users.email_confirmed_at ('' for every address saved
before it) and user_links - the SHA-256 of a link's token, its user,
purpose (confirm, reset), address, created and expiry. A changed address
loses its mark (keepConfirmed, in UpdateUser and SaveUser).

internal/web/auth/links.go. A link is 256 bits from crypto/rand, mailed as
https://SELFPOST_HOSTNAME/... - never the request's Host. Confirmation:
24 h, sent when an address is saved (Account, or the global role's user
form) and by Account's Send the link again; its page /confirm/<token> has
a button (a GET changes nothing) and confirms only for a session of its
own account. Reset: /login/reset asks for a username and answers the same
for every name (the sign-in page, "If that account has a confirmed e-mail,
the link is on its way"), mailing after the answer; only a confirmed
address gets one, none within ten minutes of the last, five links an hour
per account, five requests in 15 minutes per client address;
/login/reset/<token> (30 min) sets the password with the link taken in
the same transaction that checks the address again
(store.TakeResetLink), then ends every session. Changing the e-mail on
Account asks for the current password. A password set on Account or the
user form removes the reset links; a restore removes every link; the stop
waits for links being mailed (Server.Drain); a rejected request's log line
hides a link's token (loggedPath).

Reviewed for security before the commit (2026-10-17): no high; two
medium and five low, all fixed here - confirming needs the account's
session and the mail does not name the account (a mistyped address was a
takeover); a reset request neither replaces the links already sent nor
spends the account's quota inside ten minutes; take-and-set atomic; the
confirmation mail sent after the answer; the stop waits for mail; a
restore deletes the links; the token kept out of the log.

Tests: store TestUserLinks, TestUserLinkTakenOnce, TestEmailConfirmation,
TestTakeResetLink; auth TestResetSendsALinkOnlyToAConfirmedAddress,
TestResetLinkSetsThePasswordOnce, TestResetLinkDiesWithTheAddress,
TestResetRequestsAreLimited, TestResetRequestsAreSpaced, TestConfirmLink,
TestLinkPathsWithoutAToken; handlers TestAccountEmailIsConfirmedByItsLink,
TestUserFormSendsANewAddressItsLink; web TestLoggedPathHidesTokens; the
view's pages and fixtures; e2e password_reset_by_e_mail runs it through
the sink (and checks a link from before the restore is dead). go vet +
go test (26 packages) and make e2e on the test server for this tree.

Docs: guide § Account, security.md (the bullet and what ends sessions),
architecture (routes), schema-migrations (row 13, users, user_links),
help #account (word for word with the mockup), roadmap row done,
CHANGELOG [Unreleased].

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

internal/web/view/server_test.go

@@ -152,7 +152,7 @@ func TestUserFormShowsWhatIsStoredUnderTheHandlersFieldNames(t *testing.T) {
 	pageHas(t, "User", out,
 		`<h1 class="title is-3">acme-ops</h1>`, `href="/server/users">Users</a>`, `href="/server/users/3/delete"`,
 		`<form class="sp-form" method="post" action="/server/users/3">`,
-		`name="username" value="acme-ops"`, `<label class="label" for="email">E-mail</label>`,
+		`name="username" value="acme-ops"`, `<label class="label" for="email">E-mail <span class="tag is-success is-light">confirmed</span></label>`,
 		`<input class="input" id="email" name="email" type="email" value="ops@acme.io" autocomplete="off">`,
 		`name="password" type="password" autocomplete="new-password">`,
 		`Leave empty to keep the current one.`,
@@ -316,8 +316,9 @@ func TestEveryHelpLinkLandsOnATopic(t *testing.T) {
 // change it under Account, and it can receive DMARC reports if they choose.
 func TestUserFormEmailHelpSaysOnlyWhatIsTrue(t *testing.T) {
 	out := renderSignedIn(t, "user", userFixture())
-	pageHas(t, "User", out, `The user's own address. They can change it under Account.`)
-	pageLacks(t, "User", out, `notification`, `reset`)
+	pageHas(t, "User", out, `The user's own address. They can change it under Account. A new one is sent a link to confirm it; until it is confirmed no reset link goes to it.`,
+		`E-mail <span class="tag is-success is-light">confirmed</span>`)
+	pageLacks(t, "User", out, `notification`)
 }
 
 // A domain's report address belongs to the domain, not to a user: deleting a