Add an account block showing who is signed in

[us_account], or the Account block: the signed-in visitor's name, their
email, a Sign out link, and — only when the account books for someone
besides itself — the students it books for. A parent's first question on
seeing "signed in as Grace" is whether this is the account their children's
lessons are on.

Two decisions worth naming.

Signed out with no login page chosen, the block renders nothing. Its whole
subject is the person signed in, which a stranger is not, and a bare "you
are not signed in" in a site header is noise with no way to act on it. With
a login page chosen it offers a Sign in link instead. The editor preview is
populated regardless, so the block is never an invisible box to the person
placing it.

Signing out returns to the chosen login page, or to the current page when
there is none. A block meant for a header should not also navigate someone
somewhere when they use it; the login page wins when configured, because the
page they were on may well be members-only.

The name comes from UserName::format(), so the block never exposes a
username the way display_name can.

Also brings docs/features/editor-blocks.md back in step: it still described
"four shortcodes" and had never listed the family block.

Closes #142

Co-Authored-By: Claude Opus 5 <[email protected]>

docs/features/editor-blocks.md

@@ -1,8 +1,8 @@
 # Editor Blocks
 
-Gutenberg dynamic-block wrappers for the plugin's four front-end shortcodes,
-so the pages can be previewed and styled inside the block editor instead of
-appearing as grey shortcode text.
+Gutenberg dynamic-block wrappers for the plugin's front-end shortcodes, so the
+pages can be previewed and styled inside the block editor instead of appearing
+as grey shortcode text.
 
 ## Blocks
 
@@ -12,6 +12,8 @@ appearing as grey shortcode text.
 | `us-scheduler/student-login` | `[us_student_login]` | `Auth\LoginPage::render()` |
 | `us-scheduler/student-register` | `[us_student_register]` | `Auth\RegistrationPage::render()` |
 | `us-scheduler/group-classes` | `[us_group_classes]` | `GroupClass\GroupClassPage::render()` |
+| `us-scheduler/family` | `[us_family]` | `Guardian\FamilyPage::render()` |
+| `us-scheduler/account` | `[us_account]` | `Auth\AccountPage::render()` |
 
 The shortcodes remain registered for back-compat; blocks and shortcodes share
 the same page objects (constructed once in `Plugin::boot()`), so front-end
@@ -21,7 +23,7 @@ transform.
 
 ## Block options
 
-Four blocks have sidebar (inspector) options:
+Most blocks have sidebar (inspector) options:
 
 | Block | Attribute | Default | Effect |
 |---|---|---|---|
@@ -34,6 +36,8 @@ Four blocks have sidebar (inspector) options:
 | `us-scheduler/student-login` | `autoRedirect` (boolean) | `false` | Send logged-in visitors straight to the booking page instead of showing the link. Does nothing until a booking page is chosen. |
 | `us-scheduler/student-register` | `loginPageId` (number) | `0` | Page students continue to once registration finishes — the "Sign in to your account" link after they confirm their email, and the "Continue to your account" link an invited student gets on the spot. `0` = the WordPress login screen for the confirmation link, and no link at all for the (already signed-in) invited student. Shortcode equivalent: `[us_student_register login_page_id="…"]`. |
 | `us-scheduler/student-register` | `autoRedirect` (boolean) | `false` | Send students straight to that page instead of showing the link. Does nothing until a page is chosen — there is no login-screen fallback here. |
+| `us-scheduler/family` | `loginPageId` (number) | `0` | Where visitors who are not signed in are sent to log in. Shortcode equivalent: `[us_family login_page_id="…"]`. |
+| `us-scheduler/account` | `loginPageId` (number) | `0` | Where signing out returns to, and where a signed-out visitor is offered a **Sign in** link. `0` = signing out returns to the current page, and a signed-out visitor sees **nothing at all** — see below. Shortcode equivalent: `[us_account login_page_id="…"]`. |
 | `us-scheduler/group-classes` | `offeringId` (number) | `0` | Restrict the page to a single group class, for embedding on a page dedicated to that class. The class description is then omitted — only the schedule, instructor, price and enrolment controls are shown, so the surrounding page's own copy is not repeated. `0` = browse all classes, descriptions included. Shortcode equivalent: `[us_group_classes offering="…"]`. |
 
 The page selects list all published pages; if a chosen page is later deleted,
@@ -105,6 +109,10 @@ placeholder content:
 - **Login** — the real `templates/frontend/login-page.php` template (it has
   no request-state dependencies).
 - **Registration** — a disabled sample of the `.us-register-form` fields.
+- **Account** — a populated sample panel. Deliberately populated whatever the
+  editor user's own state: on the published page a signed-out visitor may see
+  nothing at all, and an empty box tells the person placing the block nothing
+  about where it will sit.
 
 Each preview starts with a `.us-editor-note` paragraph explaining what the
 published page shows instead. The note class only appears in editor previews.
@@ -118,5 +126,23 @@ published page shows instead. The note class only appears in editor previews.
   and fallbacks.
 - `tests/Unit/Auth/LoginPageTest.php` — logged-in booking-link targets and
   fallbacks.
+- `tests/Unit/Auth/AccountPageTest.php` — what each visitor sees, the
+  sign-out redirect target, and the signed-out empty render.
 - `tests/Unit/BlockPreviewTest.php` — preview markup mirrors the live CSS
   classes/ids and includes the editor note.
+
+## The account block's signed-out behaviour
+
+`us-scheduler/account` is the one block that can render **nothing**. It is meant
+for a header, sidebar or account page, and its whole subject is the person
+signed in — which a stranger is not. A bare "you are not signed in" in a site
+header is noise that cannot be acted on, so:
+
+- **No login page chosen** → empty string for signed-out visitors.
+- **Login page chosen** → a single **Sign in** link.
+
+Signed in, it shows the display name (`Auth\UserName::format()`, so a username
+is never exposed), the account email, a **Sign out** link, and — only on an
+account that books for someone other than itself — the students it books for.
+Signing out returns to the chosen login page, or to the current page when there
+is none, so a header sign-out does not also navigate the visitor somewhere.