feat(drive): download folder as archive

[AitiX]

Description

Adds a Download as archive action for folders in the Drive module. Previously only
individual files could be downloaded; folders with many files (e.g. build artifacts)
had to be fetched one file at a time.

The action walks the folder tree through the platform client, fetches every file blob
and packs everything into a single <folder name>.zip on the client, preserving the
relative folder structure inside the archive.

Implementation notes

• New action drive.action.DownloadFolder / drive.actionImpl.DownloadFolder,
  registered for drive.class.Folder next to the existing file Download action
  (same category, tools group, context + browser modes).
• Traversal (plugins/drive-resources/src/archive.ts): recursive
  client.findAll over drive.class.File (with $lookup of the current
  FileVersion) and drive.class.Folder, sorted by title for deterministic
  archives. A visited-set guards against cycles, and duplicate titles within one
  folder get a numeric suffix.
• Blob access reuses getFileUrl from @hcengineering/presentation (the same
  URL the file Download action uses) and plain fetch, matching how
  getJsonOrEmpty fetches blobs elsewhere in the platform.
• Zip library: fflate (^0.8.2), added
  to @hcengineering/drive-resources. No workspace package currently depends on a
  zip library directly (jszip appears in the lockfile only as a transitive
  dependency of docx tooling), so the smallest streaming option was chosen.
  Entries are added via ZipPassThrough (store, no re-compression): Drive blobs are
  typically already compressed or incompressible (archives, media, build artifacts),
  so this keeps CPU usage minimal while still producing a standard zip.
• Files are fetched sequentially; the archive is assembled in memory and saved via a
  temporary object URL. Empty folders produce no download. Errors are reported through
  setPlatformStatus(unknownError(...)), consistent with other drive-resources utils.
• Localization: new DownloadAsArchive string (en: "Download as archive",
  ru: "Скачать архивом"). Other locales fall back to English, matching existing
  partially-translated keys in drive-assets.

Changed files

• models/drive/src/index.ts — register the folder action
• models/drive/src/plugin.ts — action.DownloadFolder, actionImpl.DownloadFolder ids
• plugins/drive-resources/src/archive.ts — new: traversal + zip + save
• plugins/drive-resources/src/index.ts — DownloadFolder action implementation
• plugins/drive-resources/src/plugin.ts — DownloadAsArchive string id
• plugins/drive-resources/package.json — add fflate
• plugins/drive-assets/lang/en.json, plugins/drive-assets/lang/ru.json — new string
• common/config/rush/pnpm-lock.yaml — lockfile update for fflate

How to test

1. Open a workspace with the Drive application enabled.
2. Create a drive, add a folder with a few files and at least one nested subfolder
   with files (mixed types; ideally also two files with the same name in one folder).
3. Right-click the folder (or use the ... menu) → Download as archive.
4. A <folder name>.zip download should start; after extraction the content must
   mirror the Drive folder structure, including nested subfolders.
5. Verify an empty folder triggers no download, and a folder whose name contains
   / or \ still produces a valid archive name.
6. Regression: file Download, folder Rename/Delete/Move actions
   still work.

Checklist

• Affected packages compile (rush build --to @hcengineering/model-drive --to @hcengineering/drive-resources)
• Localized strings added (en, ru)
• Screenshots / screencast (to attach when opening the PR)