perf: move PouchDB/IndexedDB operations to a Web Worker

All database reads and writes now run off the main thread via a
dedicated worker, eliminating IndexedDB overhead from the frame budget.

- Create data.worker.ts exposing the Data class via Comlink
- Refactor data.ts to export a Comlink-wrapped proxy and a standalone
  generateId() pure function (workers can't expose sync methods cleanly)
- Update all 10 call sites to import generateId directly instead of
  calling data.generateId()

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/modules/repo/hooks/useFavoriteRepos.hook.ts

@@ -1,6 +1,6 @@
 import { computed, onMounted, ref } from "vue"
 
-import { data } from "@/data/data"
+import { data, generateId } from "@/data/data"
 import { DataType } from "@/data/DataType.enum"
 import { useRepos } from "@/hooks/useRepos.hook"
 import { RepoBase } from "@/modules/repo/interfaces/RepoBase"
@@ -27,7 +27,7 @@ export const useFavoriteRepos = () => {
 
   const toggleFavorite = async (repo: RepoBase, isFavorite: boolean) => {
     const favorite: FavoriteRepo = {
-      _id: data.generateId(DataType.FavoriteRepo, repo.id),
+      _id: generateId(DataType.FavoriteRepo, repo.id),
       $type: DataType.FavoriteRepo,
       isFavorite,
       name: repo.name,