feat: universal LLM gateway with embedded multilingual admin console

- OpenAI-compatible gateway with intelligent routing via cortiq-router (allaigate)
- Embedded build-free admin SPA at /admin: 7 languages (en/ru/de/fr/es/zh/tr),
  light/dark themes, hot config reload (no restart)
- Admin API, per-request statistics + Prometheus /metrics, secret store, playground
- English documentation (primary) with Russian translations (*.ru.md)

web/js/views/login.js

@@ -0,0 +1,40 @@
+// Login screen — admin token entry. Shown when there is no token or on 401.
+import { h } from "../ui.js";
+import { t } from "../i18n.js";
+import { setToken } from "../api.js";
+
+export function renderLogin(onOk) {
+  const input = h("input", {
+    type: "password",
+    placeholder: t("login.tokenPlaceholder"),
+    autofocus: true,
+  });
+  const submit = () => {
+    const val = input.value.trim();
+    if (!val) return;
+    setToken(val);
+    onOk();
+  };
+  input.addEventListener("keydown", (e) => {
+    if (e.key === "Enter") submit();
+  });
+  return h(
+    "div",
+    { class: "login-wrap" },
+    h(
+      "div",
+      { class: "login-card" },
+      h(
+        "div",
+        { class: "brand" },
+        h("b", { style: "font-size:20px" }, "allaigate"),
+        h("span", { class: "sub" }, t("brand.sub"))
+      ),
+      h("h2", {}, t("login.title")),
+      h("p", { class: "sub" }, t("login.subtitle")),
+      h("label", { class: "field" }, h("span", {}, t("login.token")), input),
+      h("button", { class: "btn primary", style: "width:100%", onClick: submit }, t("login.submit")),
+      h("p", { class: "hint", style: "margin-top:16px" }, t("login.hint"))
+    )
+  );
+}