feat: rebuild fiscal clone architecture and harden coolify deployment

frontend/hooks/use-auth-guard.ts

@@ -0,0 +1,22 @@
+'use client';
+
+import { useEffect } from 'react';
+import { useRouter } from 'next/navigation';
+import { useSession } from '@/lib/better-auth';
+
+export function useAuthGuard() {
+  const { data: session, isPending } = useSession();
+  const router = useRouter();
+
+  useEffect(() => {
+    if (!isPending && !session) {
+      router.replace('/auth/signin');
+    }
+  }, [isPending, session, router]);
+
+  return {
+    session,
+    isPending,
+    isAuthenticated: Boolean(session?.user)
+  };
+}

frontend/hooks/use-task-poller.ts

@@ -0,0 +1,59 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { getTask } from '@/lib/api';
+import type { Task } from '@/lib/types';
+
+type UseTaskPollerInput = {
+  taskId: string | null;
+  intervalMs?: number;
+  onTerminalState?: (task: Task) => void;
+};
+
+export function useTaskPoller({ taskId, intervalMs = 2200, onTerminalState }: UseTaskPollerInput) {
+  const [task, setTask] = useState<Task | null>(null);
+
+  useEffect(() => {
+    if (!taskId) {
+      setTask(null);
+      return;
+    }
+
+    let stopped = false;
+    let timer: ReturnType<typeof setTimeout> | null = null;
+
+    const poll = async () => {
+      try {
+        const { task: latest } = await getTask(taskId);
+
+        if (stopped) {
+          return;
+        }
+
+        setTask(latest);
+
+        if (latest.status === 'completed' || latest.status === 'failed') {
+          onTerminalState?.(latest);
+          return;
+        }
+      } catch {
+        if (stopped) {
+          return;
+        }
+      }
+
+      timer = setTimeout(poll, intervalMs);
+    };
+
+    void poll();
+
+    return () => {
+      stopped = true;
+      if (timer) {
+        clearTimeout(timer);
+      }
+    };
+  }, [taskId, intervalMs, onTerminalState]);
+
+  return task;
+}