Add Administration, starting with accounts

An account whose Stalwart role manages accounts now finds Administration in
the account menu. It lists, searches, creates and edits accounts -- display
name, other addresses, role, storage limit -- sets a new password, and
deletes, each offered only when the role holds the matching permission.

The server keeps the permissions list from GET /api/account, which it
already called for the edition and threw the rest away. Everything else is
JMAP x:Account, x:Domain and x:Role calls through the existing /api/jmap
proxy, so nothing new is stored and Stalwart decides every call.

Stalwart checks a grant against the caller's permissions but not a password
change or a delete, so an account that outranks the viewer is shown
read-only. Your own password is changed in Settings, which re-seals the
session; changing it here would strand it.

The mock server gains a directory behind the same permission names, with
MOCK_ROLE choosing admin, tenant-admin, helpdesk or user.

68 new strings, translated in all nine catalogues; strings falling back to
English stay at 16.

web/src/views/admin/directoryContext.ts

@@ -0,0 +1,25 @@
+import type { RoleDef } from "@/lib/adminAccess";
+import type { DirectoryAccount, DirectoryDomain } from "@/lib/adminDirectory";
+import { t } from "@/lib/i18n";
+
+export interface DirectoryContext {
+  /** Domains to offer. Read from the server when allowed, else seen on accounts. */
+  domains: DirectoryDomain[];
+  /** Null when the viewer cannot read roles, which `outranks` treats as unknown. */
+  roles: Map<string, RoleDef> | null;
+  groups: Map<string, DirectoryAccount>;
+  /** Registry ids and addresses that are the signed-in account itself. */
+  self: { ids: Set<string>; address: string };
+}
+
+export function isSelf(a: Pick<DirectoryAccount, "id" | "emailAddress">, ctx: DirectoryContext): boolean {
+  return ctx.self.ids.has(a.id) || (!!a.emailAddress && a.emailAddress.toLowerCase() === ctx.self.address);
+}
+
+export function roleName(a: Pick<DirectoryAccount, "roles">, roles: Map<string, RoleDef> | null): string {
+  const r = a.roles;
+  if (!r || r["@type"] === "User") return t("User");
+  if (r["@type"] === "Admin") return t("Administrator");
+  const names = Object.keys(r.roleIds ?? {}).map((id) => roles?.get(id)?.description).filter(Boolean);
+  return names.length ? names.join(", ") : t("Custom role");
+}