feat(gateway): show action result toasts

app/gateway-frontend/src/composables/useToast.ts

@@ -0,0 +1,59 @@
+import { readonly, ref } from 'vue';
+
+export type ToastKind = 'success' | 'error' | 'info';
+
+export type Toast = {
+    id: number;
+    kind: ToastKind;
+    message: string;
+};
+
+const visibleToasts = ref<Toast[]>([]);
+const dismissTimers = new Map<number, ReturnType<typeof setTimeout>>();
+let nextToastId = 1;
+
+const dismiss = (id: number): void => {
+    const timer = dismissTimers.get(id);
+    if (timer) clearTimeout(timer);
+    dismissTimers.delete(id);
+    visibleToasts.value = visibleToasts.value.filter((toast) => toast.id !== id);
+};
+
+const show = (message: string, kind: ToastKind = 'info', durationMs = 5_000): number => {
+    const normalizedMessage = message.trim();
+    if (!normalizedMessage) return -1;
+
+    const duplicate = visibleToasts.value.find(
+        (toast) => toast.message === normalizedMessage && toast.kind === kind
+    );
+    if (duplicate) {
+        dismiss(duplicate.id);
+    }
+
+    const id = nextToastId++;
+    visibleToasts.value = [...visibleToasts.value.slice(-3), { id, kind, message: normalizedMessage }];
+    if (durationMs > 0) {
+        dismissTimers.set(id, setTimeout(() => dismiss(id), durationMs));
+    }
+    return id;
+};
+
+const feedback = (message: string): number => {
+    if (/실패|오류|못했|필요|입력|선택|유효|일치하지|비활성화|없습니다|해야 합니다/.test(message)) {
+        return show(message, 'error');
+    }
+    if (/완료|성공|저장|등록|적용|변경|해제|부여|생성|철회|예약/.test(message)) {
+        return show(message, 'success');
+    }
+    return show(message, 'info');
+};
+
+export const useToast = () => ({
+    toasts: readonly(visibleToasts),
+    show,
+    success: (message: string, durationMs?: number) => show(message, 'success', durationMs),
+    error: (message: string, durationMs?: number) => show(message, 'error', durationMs),
+    info: (message: string, durationMs?: number) => show(message, 'info', durationMs),
+    feedback,
+    dismiss,
+});