Celerp 2.5.4 ڈاؤن لوڈ

<!-- Release notes generated using configuration in .github/release.yml at v2.5.4 -->

## What's Changed
• Move a company from Manager.io into Celerp by @ngsevers in https://github.com/celerp/celerp/pull/358
• Simpler data import during company setup, with Excel support by @ngsevers in https://github.com/celerp/celerp/pull/360
• Company backups：download and restore one company by @ngsevers in https://github.com/celerp/celerp/pull/361
• Update notice stays visible after you change pages by @ngsevers in https://github.com/celerp/celerp/pull/364
• Postings use each company's own posting accounts by @ngsevers in https://github.com/celerp/celerp/pull/366
• Safer company backups, smoother moves from other systems, and a reviewed inventory import by @ngsevers in https://github.com/celerp/celerp/pull/367
• Faster lock, import and module install tests with tighter checks by @ngsevers in https://github.com/celerp/celerp/pull/370
• Celerp 2.5.4 release prep hardening by @ngsevers in https://github.com/celerp/celerp/pull/371
• Scan several labels into the inventory search and see exactly those items by @ngsevers in https://github.com/celerp/celerp/pull/377
• Nightly upgrade check runs again on Linux and Windows by @ngsevers in https://github.com/celerp/celerp/pull/378
• Consignment sales, document import choices, returns and line actions by @ngsevers in https://github.com/celerp/celerp/pull/375
• Installers are upgrade-tested before a release is published by @ngsevers in https://github.com/celerp/celerp/pull/379
• Clearer error messages, in every language by @ngsevers in https://github.com/celerp/celerp/pull/380

**Full Changelog**：https://github.com/celerp/celerp/compare/v2.5.3...v2.5.4