feat: 네이티브 alert/confirm/prompt → 공용 인앱 다이얼로그 (PC 'sb_pt' 제거)

- composables/dialog + components/ui/AppDialog(App 루트 마운트)
- window.alert 전역 오버라이드로 모든 alert 인앱화
- confirm/prompt(동기)는 각 호출부를 await dialog.confirm/prompt 로 교체
  (가계부·예산·고정지출·계좌·태그·관리자·게시판·설정 — 삭제/열람제한 등)
- 웹/PC/APK 일관 UI, 의미있는 제목 부여

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/ui/AppDialog.vue

@@ -0,0 +1,121 @@
+<script setup>
+import { nextTick, watch, ref } from 'vue'
+import { dialogState, dialogConfirm, dialogCancel } from '@/composables/dialog'
+
+const inputEl = ref(null)
+// prompt 열릴 때 입력칸 포커스
+watch(
+  () => dialogState.open,
+  async (open) => {
+    if (open && dialogState.type === 'prompt') {
+      await nextTick()
+      inputEl.value?.focus()
+    }
+  },
+)
+</script>
+
+<template>
+  <Teleport to="body">
+    <Transition name="dlg-fade">
+      <div v-if="dialogState.open" class="dlg-backdrop" @click.self="dialogCancel">
+        <div class="dlg" role="dialog" aria-modal="true">
+          <h2 class="dlg-title">{{ dialogState.title }}</h2>
+          <p v-if="dialogState.message" class="dlg-msg">{{ dialogState.message }}</p>
+          <input
+            v-if="dialogState.type === 'prompt'"
+            ref="inputEl"
+            v-model="dialogState.inputValue"
+            class="dlg-input"
+            :placeholder="dialogState.placeholder"
+            @keyup.enter="dialogConfirm"
+          />
+          <div class="dlg-buttons">
+            <button v-if="dialogState.type !== 'alert'" type="button" class="dlg-btn" @click="dialogCancel">
+              {{ dialogState.cancelText }}
+            </button>
+            <button type="button" class="dlg-btn primary" :class="{ danger: dialogState.danger }" @click="dialogConfirm">
+              {{ dialogState.okText }}
+            </button>
+          </div>
+        </div>
+      </div>
+    </Transition>
+  </Teleport>
+</template>
+
+<style scoped>
+.dlg-backdrop {
+  position: fixed;
+  inset: 0;
+  z-index: 2000;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  background: rgba(0, 0, 0, 0.5);
+  padding: 1rem;
+}
+.dlg {
+  position: relative;
+  width: 100%;
+  max-width: 340px;
+  padding: 1.4rem 1.25rem calc(1.25rem + env(safe-area-inset-bottom));
+  background: var(--color-background);
+  border: 1px solid var(--color-border);
+  border-radius: 12px;
+  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
+}
+.dlg-title {
+  font-size: 1.05rem;
+  margin: 0 0 0.6rem;
+}
+.dlg-msg {
+  margin: 0 0 1rem;
+  font-size: 0.9rem;
+  line-height: 1.55;
+  white-space: pre-line;
+}
+.dlg-input {
+  width: 100%;
+  box-sizing: border-box;
+  padding: 0.5rem 0.7rem;
+  margin-bottom: 1rem;
+  border: 1px solid var(--color-border);
+  border-radius: 6px;
+  background: var(--color-background-soft);
+  color: var(--color-text);
+  font: inherit;
+}
+.dlg-buttons {
+  display: flex;
+  justify-content: flex-end;
+  gap: 0.5rem;
+}
+.dlg-btn {
+  padding: 0.45rem 1rem;
+  border: 1px solid var(--color-border);
+  border-radius: 6px;
+  background: var(--color-background-soft);
+  color: var(--color-text);
+  font: inherit;
+  cursor: pointer;
+}
+.dlg-btn.primary {
+  background: hsla(160, 100%, 37%, 1);
+  border-color: hsla(160, 100%, 37%, 1);
+  color: #fff;
+  font-weight: 600;
+}
+.dlg-btn.primary.danger {
+  background: #c0392b;
+  border-color: #c0392b;
+}
+.dlg-fade-enter-active,
+.dlg-fade-leave-active {
+  transition: opacity 0.15s;
+}
+.dlg-fade-enter-from,
+.dlg-fade-leave-to {
+  opacity: 0;
+}
+</style>