feat: add auth subsystem with WebAuthn passkeys support

New modules: lib/auth, lib/auth_users, lib/db, lib/db_sqlite, lib/password,
lib/webauthn, daemon/handlers/auth, scripts/bootstrap_auth, tests/test_auth

Frontend: webui/api/auth, hoover/components/auth, pages/login, passkeys, users

Updates: daemon/iface and server, lib/common and nginx, pyproject.toml deps,
install script, server.py, app.js, and websocket/api clients

webui/static/hoover/components/modal.js

@@ -191,7 +191,8 @@ export function formModal(inner, title, fields, actions) {
         if (a.handler) {
             const origHandler = a.handler;
             btn.addEventListener('click', () => {
-                refreshModals();
+                btn.disabled = true;
+                btn.innerHTML = '<span class="btn-spinner"></span>';
                 origHandler();
             });
         }