Support importing multiple collections at once

[artumex]

Currently, Solo only allows importing one collection at a time. When migrating from Postman or working on large projects (especially microservices architectures), users often need to import dozens of collections. Repeating the import process manually for each file is very tedious and time-consuming.
It would be great to have the ability to import multiple collections in a single operation.

[speziato]

Thank you for the feature request! We actually discussed this some time ago, and we put it in our mental backlog as something to be implemented after the first public release. I would extend this approach to Environments as well.

The current logic allows only one file (or folder, for Bruno collections) path for both the file picker and the backend importing functions. The batch import implementation could be done with a simple, mostly-frontend change (e.g.: allow multiple files/folders in the picker + multiple import function invocations with Promise.allSettled), but I think a better approach would be to change the whole flow, including go functions, to accept a list of paths and let the backend decide on concurrency and locking mechanisms. This would scale better in case users import tens of files at once.

Error handling now is done by just showing a toast notification on failure, which is fine for a single path import. With the batch logic (regardless of which approach we will choose for the implementation), we will need to also rethink how to show both import progress and errors to users.

If you want, you can propose an implementation in a PR! Let us know. In the meantime, thank you again