feat(chat): preserve message drafts in session temp store

frontend/tests/helpers/chat-drafts.cjs

@@ -0,0 +1,36 @@
+const fs = require('node:fs')
+const vm = require('node:vm')
+const { randomUUID } = require('node:crypto')
+const vue = require('vue')
+
+function memoryStorage() {
+  const storage = Object.create(null)
+  Object.defineProperties(storage, {
+    getItem: { value: key => storage[key] ?? null },
+    setItem: { value: (key, value) => { storage[key] = value } },
+    removeItem: { value: key => { delete storage[key] } },
+  })
+  return storage
+}
+
+function createDraftHarness({ auth = vue.reactive({ user: { id: 'user-1' }, activeTenant: '1', profile: { id: 'profile-1' } }), storage = memoryStorage() } = {}) {
+  const scope = vue.effectScope(), toasts = [], calls = []
+  const context = vm.createContext({ ...vue, crypto: { randomUUID }, sessionStorage: storage,
+    defineStore: (_, setup) => setup,
+    useAuthStore: () => auth,
+    useRuntimeConfig: () => ({ public: { apiBase: 'https://api.example.test' } }),
+    useToast: () => ({ add: toast => toasts.push(toast) }),
+    useNuxtApp: () => ({ $api: async (url, options) => { calls.push({ url, options }) } }),
+  })
+  const storeSource = fs.readFileSync(`${__dirname}/../../stores/temp.js`, 'utf8').replace(/^import .*$/mg, '').replace('export const', 'const')
+  const store = scope.run(() => vm.runInContext(`${storeSource}\nuseTempStore()`, context))
+  context.useTempStore = () => store
+  const composable = fs.readFileSync(`${__dirname}/../../composables/useChatDraft.js`, 'utf8').replace('export function', 'function')
+  vm.runInContext(composable, context)
+  return { auth, storage, store, calls, toasts,
+    useChatDraft: (key, options) => scope.run(() => context.useChatDraft(key, options)),
+    close: () => scope.stop(),
+  }
+}
+
+module.exports = { createDraftHarness, memoryStorage }