✨ Añade pagetop-user, con autenticación y RBAC

Identidad de usuario, sesiones en base de datos, roles y permisos (RBAC)
con "authenticated" implícito, contraseñas con Argon2id, tokens de
un solo uso para verificación de email y restablecimiento de contraseña,
y la UI de administración completa (usuarios, roles, permisos) sobre
pagetop-admin.

Incluye datos de demostración opcionales tras la feature `demo-data`.

extensions/pagetop-user/src/locale/en-US/common.ftl

@@ -0,0 +1,154 @@
+## pagetop-user — English (default)
+
+# **< Extension metadata >**
+
+extension_name        = PageTop User
+extension_description = User identity, authentication, roles and permissions for PageTop.
+
+# **< Page titles >**
+
+title-login          = Sign in
+title-register       = Create account
+title-password-reset = Reset password
+title-new-password   = Set new password
+title-profile        = My profile
+
+# **< Field labels >**
+
+field-username         = Username or email
+field-password         = Password
+field-email            = Email address
+field-confirm-password = Confirm password
+field-new-password     = New password
+field-remember-me      = Remember me
+
+# **< Buttons and links >**
+
+btn-login           = Sign in
+btn-logout          = Sign out
+btn-register        = Create account
+btn-send-reset-link = Send reset link
+btn-set-password    = Change password
+
+link-register        = Create an account
+link-forgot-password = Forgot your password?
+link-back-to-login   = Back to sign in
+
+# **< Messages >**
+
+msg-password-reset-sent =
+    If an account with that email exists, we have sent a reset link.
+    Please check your inbox.
+
+# **< Error messages >**
+
+error-invalid-credentials   = Invalid username or password.
+error-account-blocked       = Your account is blocked. Please contact the administrator.
+error-account-pending       = Please verify your email address before signing in.
+error-account-locked        = Too many failed attempts. Please try again later.
+error-password-mismatch     = Passwords do not match.
+error-password-too-short    = Password must be at least { $n } characters.
+error-username-taken        = This username is already taken.
+error-email-taken           = This email address is already registered.
+error-token-invalid         = This link is invalid or has expired.
+error-internal              = An unexpected error occurred. Please try again.
+
+# **< Account statuses >**
+
+status-active  = Active
+status-blocked = Blocked
+status-pending = Pending email verification
+
+# **< Admin: page titles >**
+
+title-admin-users            = Users
+title-admin-user-new         = New user
+title-admin-user-edit        = Edit user
+title-admin-user-view        = View user
+title-admin-user-roles       = User roles
+title-admin-user-password    = Reset password
+title-admin-roles            = Roles
+title-admin-role-new         = New role
+title-admin-role-edit        = Edit role
+title-admin-role-view        = View role
+title-admin-role-permissions = Role permissions
+title-admin-permissions      = Permissions
+title-user-details           = User details
+title-role-details           = Role details
+
+# **< Admin: page descriptions >**
+
+description-admin-users       = Manage user accounts and access.
+description-admin-roles       = Manage roles and their permissions.
+description-admin-permissions = Browse the permission catalog by extension.
+
+# **< Admin: table columns >**
+
+col-username     = Username
+col-email        = Email
+col-display-name = Display name
+col-roles        = Roles
+col-status       = Status
+col-actions      = Actions
+col-machine-name = Machine name
+col-label        = Label
+col-type         = Type
+col-users-count  = Users
+
+# **< Admin: field labels >**
+
+field-username-admin = Username
+field-display-name   = Display name
+field-language       = Language
+field-timezone       = Timezone
+field-machine-name   = Machine name
+field-label          = Label
+field-description    = Description
+field-weight         = Weight
+field-roles          = Roles
+field-is-admin       = Administrator (unrestricted access)
+field-search-users   = Search by username, email or name...
+
+help-machine-name-immutable =
+    Lowercase letters, digits and underscores only. Cannot be changed after creation.
+
+# **< Admin: buttons and links >**
+
+btn-save               = Save
+btn-create-user        = New user
+btn-create-role        = New role
+btn-delete             = Delete
+btn-cancel             = Cancel
+btn-edit               = Edit
+btn-manage-roles       = Manage roles
+btn-manage-permissions = Manage permissions
+btn-reset-password     = Reset password
+btn-block               = Block
+btn-activate            = Activate
+btn-grant-admin        = Grant administrator
+btn-revoke-admin       = Revoke administrator
+link-back-to-list      = Back to list
+
+# **< Admin: confirmations and badges >**
+
+confirm-delete-role   = Delete this role? This cannot be undone.
+confirm-change-status = Change this account's status?
+confirm-grant-admin   = Grant unrestricted access to this account?
+confirm-revoke-admin  = Revoke this account's unrestricted access?
+badge-system-role     = System
+badge-admin           = Administrator
+empty-users-list      = No users found.
+empty-roles-list      = No roles found.
+
+# **< Admin: error messages >**
+
+error-role-not-found              = Role not found.
+error-role-machine-name-taken     = This machine name is already taken.
+error-invalid-machine-name        = Machine name may only contain lowercase letters, digits and underscores.
+error-role-locked                  = This role is a system role and cannot be modified.
+error-role-in-use                 = This role has users assigned and cannot be deleted.
+error-last-administrator          = Cannot remove the last administrator.
+error-cannot-block-self           = You cannot block your own account.
+error-cannot-modify-own-admin-flag = You cannot grant or revoke your own unrestricted access.
+error-user-not-found              = User not found.
+error-unknown-permission          = Unknown permission key.