feat(cabana): add the My account page with subtitle and password change

- lagoon: 202610090001_backend_users_metadata adds WinterCMS's nullable
  jsonable backend_users.metadata column (TEXT); rollback drops only it
- cabana.BackendUser.Metadata and Subtitle read metadata.subtitle leniently
  (NULL, blank, null, [], invalid JSON and non-strings read as empty)
- GET /auth/me returns subtitle; PUT /account edits the signed-in admin's
  own names, email and subtitle, and the password with current_password;
  any other key is a 422 and nothing is written
- email: required, valid, 6-255 chars, unique against other admins' email
  and login ignoring case (soft-deleted included); a unique-index race is 422
- a password change sets tokens_valid_after, revokes the presented token and
  gives a cookie session a fresh cookie
- swag annotation, regenerated admin.json and schema.d.ts; route inventories,
  CSRF walk (27) and OpenAPI conformance learn the route
- SPA: My account item in the user menu opens /account (AccountView), which
  saves through PUT /account and updates the top bar via setCurrentUser
- backend::lang.myaccount strings (en, pl), rebuilt boardwalk dist
- cabana and lagoon READMEs, users-and-permissions and admin-spa docs

admin/src/app/pageTitle.ts

@@ -15,6 +15,9 @@ export function pageIndicator(route: RouteLocationNormalizedLoaded): string {
   if (route.name === 'settings') {
     return t('backend::lang.settings.title')
   }
+  if (route.name === 'account') {
+    return t('backend::lang.myaccount.menu_label')
+  }
   if (route.name === 'settings-form') {
     return settingsEntry(String(route.params.code ?? ''))?.label ?? String(route.params.code ?? '')
   }

admin/src/app/router.ts

@@ -10,6 +10,7 @@ import FormView from '../views/FormView.vue'
 import PreviewView from '../views/PreviewView.vue'
 import SettingsFormView from '../views/SettingsFormView.vue'
 import SettingsIndexView from '../views/SettingsIndexView.vue'
+import AccountView from '../views/AccountView.vue'
 import NotFoundView from '../views/NotFoundView.vue'
 
 declare module 'vue-router' {
@@ -67,6 +68,8 @@ export function createAdminRouter(history: RouterHistory = createWebHistory(runt
       },
       { path: '/settings', name: 'settings', component: SettingsIndexView, meta: { shell: true } },
       { path: '/settings/:code', name: 'settings-form', component: SettingsFormView, meta: { shell: true } },
+      // My account: the signed-in admin's own profile and password.
+      { path: '/account', name: 'account', component: AccountView, meta: { shell: true } },
       { path: '/:vendor/:plugin/:controller', name: 'list', component: ListView, meta: { shell: true } },
       { path: '/:vendor/:plugin/:controller/create', name: 'create', component: FormView, meta: { shell: true } },
       { path: '/:vendor/:plugin/:controller/:id(\\d+)', name: 'record', component: FormView, meta: { shell: true } },