feat(extension): 浏览器插件 P1 MVP

新建 BillNote_extension/ 工作空间（基于 vitesse-webext 骨架，Vue 3 + Vite + UnoCSS + MV3）。

P1 MVP 范围：
- popup：自动读当前 tab URL，识别 Bilibili / YouTube / 抖音 / 快手；提交 /generate_note 后轮询 /task_status；展示 markdown，复制 + 下载 .md
- options：后端地址输入与连通性测试；从 /get_all_providers + /get_models_by_provider 拉供应商/模型列表；默认画质、截图/跳转、笔记风格
- chrome.storage.local 持久化设置与最近 30 个任务，popup 重开恢复进行中任务
- markdown 里的 /static/screenshots 路径在渲染前重写为绝对地址

后端：CORS 改用 regex，新增允许 chrome-extension:// 与 moz-extension:// 源（同时保留 localhost / 127.0.0.1 / tauri.localhost）。无新增 backend endpoint。

P2-P4（content script 悬浮按钮、cookie 直通、side panel、思维导图、RAG 问答）保留 stub 文件，不在本次范围。

去掉 vitesse-webext 自带的 simple-git-hooks postinstall 配置——它会在仓库根装 pre-commit 钩子去跑 pnpm lint-staged，但仓库根没有 package.json，会破坏所有提交流。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

BillNote_extension/src/composables/useWebExtensionStorage.ts

@@ -0,0 +1,166 @@
+import { StorageSerializers } from '@vueuse/core'
+import { pausableWatch, toValue, tryOnScopeDispose } from '@vueuse/shared'
+import { ref, shallowRef } from 'vue-demi'
+import { storage } from 'webextension-polyfill'
+
+import type {
+  StorageLikeAsync,
+  UseStorageAsyncOptions,
+} from '@vueuse/core'
+import type { MaybeRefOrGetter, RemovableRef } from '@vueuse/shared'
+import type { Ref } from 'vue-demi'
+import type { Storage } from 'webextension-polyfill'
+
+export type WebExtensionStorageOptions<T> = UseStorageAsyncOptions<T>
+
+// https://github.com/vueuse/vueuse/blob/658444bf9f8b96118dbd06eba411bb6639e24e88/packages/core/useStorage/guess.ts
+export function guessSerializerType(rawInit: unknown) {
+  return rawInit == null
+    ? 'any'
+    : rawInit instanceof Set
+      ? 'set'
+      : rawInit instanceof Map
+        ? 'map'
+        : rawInit instanceof Date
+          ? 'date'
+          : typeof rawInit === 'boolean'
+            ? 'boolean'
+            : typeof rawInit === 'string'
+              ? 'string'
+              : typeof rawInit === 'object'
+                ? 'object'
+                : Number.isNaN(rawInit)
+                  ? 'any'
+                  : 'number'
+}
+
+const storageInterface: StorageLikeAsync = {
+  removeItem(key: string) {
+    return storage.local.remove(key)
+  },
+
+  setItem(key: string, value: string) {
+    return storage.local.set({ [key]: value })
+  },
+
+  async getItem(key: string) {
+    const storedData = await storage.local.get(key)
+
+    return storedData[key] as string
+  },
+}
+
+/**
+ * https://github.com/vueuse/vueuse/blob/658444bf9f8b96118dbd06eba411bb6639e24e88/packages/core/useStorageAsync/index.ts
+ *
+ * @param key
+ * @param initialValue
+ * @param options
+ */
+export function useWebExtensionStorage<T>(
+  key: string,
+  initialValue: MaybeRefOrGetter<T>,
+  options: WebExtensionStorageOptions<T> = {},
+): { data: RemovableRef<T>, dataReady: Promise<T> } {
+  const {
+    flush = 'pre',
+    deep = true,
+    listenToStorageChanges = true,
+    writeDefaults = true,
+    mergeDefaults = false,
+    shallow,
+    eventFilter,
+    onError = (e) => {
+      console.error(e)
+    },
+  } = options
+
+  const rawInit: T = toValue(initialValue)
+  const type = guessSerializerType(rawInit)
+
+  const data = (shallow ? shallowRef : ref)(initialValue) as Ref<T>
+  const serializer = options.serializer ?? StorageSerializers[type]
+
+  async function read(event?: { key: string, newValue: string | null }) {
+    if (event && event.key !== key)
+      return
+
+    try {
+      const rawValue = event ? event.newValue : await storageInterface.getItem(key)
+      if (rawValue == null) {
+        data.value = rawInit
+        if (writeDefaults && rawInit !== null)
+          await storageInterface.setItem(key, await serializer.write(rawInit))
+      }
+      else if (mergeDefaults) {
+        const value = await serializer.read(rawValue) as T
+        if (typeof mergeDefaults === 'function')
+          data.value = mergeDefaults(value, rawInit)
+        else if (type === 'object' && !Array.isArray(value))
+          data.value = { ...(rawInit as Record<keyof unknown, unknown>), ...(value as Record<keyof unknown, unknown>) } as T
+        else data.value = value
+      }
+      else {
+        data.value = await serializer.read(rawValue) as T
+      }
+    }
+    catch (error) {
+      onError(error)
+    }
+  }
+
+  const dataReadyPromise = new Promise<T>((resolve, reject) => {
+    read().then(() => resolve(data.value)).catch(reject)
+  })
+
+  async function write() {
+    try {
+      await (
+        data.value == null
+          ? storageInterface.removeItem(key)
+          : storageInterface.setItem(key, await serializer.write(data.value))
+      )
+    }
+    catch (error) {
+      onError(error)
+    }
+  }
+
+  const { pause: pauseWatch, resume: resumeWatch } = pausableWatch(
+    data,
+    write,
+    {
+      flush,
+      deep,
+      eventFilter,
+    },
+  )
+
+  if (listenToStorageChanges) {
+    const listener = async (changes: Record<string, Storage.StorageChange>) => {
+      try {
+        pauseWatch()
+        for (const [key, change] of Object.entries(changes)) {
+          await read({
+            key,
+            newValue: change.newValue as string | null,
+          })
+        }
+      }
+      finally {
+        resumeWatch()
+      }
+    }
+
+    storage.onChanged.addListener(listener)
+
+    tryOnScopeDispose(() => {
+      storage.onChanged.removeListener(listener)
+    })
+  }
+
+  return {
+    data: data as RemovableRef<T>,
+    dataReady: dataReadyPromise,
+  }
+}