feat: migrate to Next.js for Mini App and enhance project structure

- Replaced the previous webapp with a new Mini App built using Next.js, improving performance and maintainability.
- Updated the `.gitignore` to exclude Next.js build artifacts and node modules.
- Revised documentation in `AGENTS.md`, `README.md`, and `architecture.md` to reflect the new Mini App structure and technology stack.
- Enhanced Dockerfile to support the new build process for the Next.js application.
- Updated CI workflow to build and test the Next.js application.
- Added new configuration options for the Mini App, including `MINI_APP_SHORT_NAME` for improved deep linking.
- Refactored frontend testing setup to accommodate the new structure and testing framework.
- Removed legacy webapp files and dependencies to streamline the project.

webapp-next/src/hooks/use-app-init.ts

@@ -0,0 +1,63 @@
+/**
+ * Application initialization: language sync, access-denied logic, deep link routing.
+ * Runs effects that depend on Telegram auth (isAllowed, startParam); caller provides those.
+ */
+
+"use client";
+
+import { useEffect } from "react";
+import { useAppStore } from "@/store/app-store";
+import { getLang } from "@/i18n/messages";
+import { useTranslation } from "@/i18n/use-translation";
+import { RETRY_DELAY_MS } from "@/lib/constants";
+
+export interface UseAppInitParams {
+  /** Whether the user is allowed (localhost or has valid initData). */
+  isAllowed: boolean;
+  /** Telegram Mini App start_param (e.g. "duty" for current duty deep link). */
+  startParam: string | undefined;
+}
+
+/**
+ * Syncs language from backend config, applies document lang/title, handles access denied
+ * when not allowed, and routes to current duty view when opened via startParam=duty.
+ */
+export function useAppInit({ isAllowed, startParam }: UseAppInitParams): void {
+  const setLang = useAppStore((s) => s.setLang);
+  const lang = useAppStore((s) => s.lang);
+  const setAccessDenied = useAppStore((s) => s.setAccessDenied);
+  const setLoading = useAppStore((s) => s.setLoading);
+  const setCurrentView = useAppStore((s) => s.setCurrentView);
+  const { t } = useTranslation();
+
+  // Sync lang from backend config (window.__DT_LANG).
+  useEffect(() => {
+    if (typeof window === "undefined") return;
+    setLang(getLang());
+  }, [setLang]);
+
+  // Apply lang to document (title and html lang) for accessibility and i18n.
+  useEffect(() => {
+    if (typeof document === "undefined") return;
+    document.documentElement.lang = lang;
+    document.title = t("app.title");
+  }, [lang, t]);
+
+  // When not allowed (no initData and not localhost), show access denied after delay.
+  useEffect(() => {
+    if (isAllowed) {
+      setAccessDenied(false);
+      return;
+    }
+    const id = setTimeout(() => {
+      setAccessDenied(true);
+      setLoading(false);
+    }, RETRY_DELAY_MS);
+    return () => clearTimeout(id);
+  }, [isAllowed, setAccessDenied, setLoading]);
+
+  // When opened via deep link startParam=duty, show current duty view first.
+  useEffect(() => {
+    if (startParam === "duty") setCurrentView("currentDuty");
+  }, [startParam, setCurrentView]);
+}