fix: clean up downloaded zip files

[pupuking723]

Fixes silexlabs/Silex#1725.

This updates the Download connector route so generated zip files are removed from the OS temp directory after a successful res.sendFile() transfer. Failed downloads keep the zip in place so the user can retry.

It also rejects unsafe :tmpZipFile parameters containing path separators or .., so the download route cannot be used to read files outside the temp directory.

Verification:

• yarn test src/ts/plugins/server/DownloadConnector.test.ts --runInBand
• yarn lint --quiet src/ts/plugins/server/DownloadConnector.ts src/ts/plugins/server/DownloadConnector.test.ts
• yarn build:plugins:server
• git diff --check

Note: the local pre-commit hook reran yarn install, but that hook failed after the verified checks above because the sandboxed environment could not resolve registry.yarnpkg.com.

[lexoyo]

Nice! Thank you @pupuking723 !
I'll take a look very soon :))