feat(import): read the exports of GOG Galaxy, Grouvee, HowLongToBeat and Playnite

README.md

@@ -42,6 +42,13 @@ To Be Played is split into three repositories:
   progress, and "Try again" for an import that stopped. The review shows the best match, other candidates and
   "search again", with the platform and status per line. Only sure matches are checked. Earlier imports can be
   undone.
+- **Export files** in the same file field, told apart by their header (`src/utils/importFormats.js`): GOG Galaxy 2.0
+  (the community script [GOG-Galaxy-Export-Script](https://github.com/AB1908/GOG-Galaxy-Export-Script), minutes),
+  Grouvee (Settings, "Export your collection", shelves as status, the wish list is left out), HowLongToBeat (its CSV
+  export, the lists as status, "Ignored" left out) and Playnite (the add-on "Library Exporter Advanced", completion
+  status, seconds). Store and platform names become IGDB abbreviations (`platformFromNames`); an unknown one stays
+  empty and the review preselects. **Unverified:** each format is built from the exporter's public source, not from
+  a real file; the test files in `src/test/fixtures/import` are made up.
 - **Platform everywhere**: each game shows its platform ("Steam" for Steam games). The favorite platform from the
   settings is preselected when a game is on it; otherwise a game on one platform gets that one, and a game on
   several waits for the user's pick.