fix: plans store使用api()替代不存在的requestJSON

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/stores/plans.js

@@ -1,6 +1,6 @@
 import { defineStore } from 'pinia'
 import { ref, computed } from 'vue'
-import { requestJSON, api } from '../composables/useApi'
+import { api } from '../composables/useApi'
 
 export const usePlansStore = defineStore('plans', () => {
   const plans = ref([])
@@ -11,11 +11,13 @@ export const usePlansStore = defineStore('plans', () => {
   const pendingPlans = computed(() => plans.value.filter(p => p.status === 'pending'))
 
   async function loadPlans() {
-    plans.value = await requestJSON('/api/oil-plans')
+    const res = await api('/api/oil-plans')
+    if (res.ok) plans.value = await res.json()
   }
 
   async function loadTeachers() {
-    teachers.value = await requestJSON('/api/teachers')
+    const res = await api('/api/teachers')
+    if (res.ok) teachers.value = await res.json()
   }
 
   async function createPlan(healthDesc, teacherId) {
@@ -50,7 +52,8 @@ export const usePlansStore = defineStore('plans', () => {
   }
 
   async function loadShoppingList(planId) {
-    shoppingList.value = await requestJSON(`/api/oil-plans/${planId}/shopping-list`)
+    const res = await api(`/api/oil-plans/${planId}/shopping-list`)
+    if (res.ok) shoppingList.value = await res.json()
   }
 
   return {