sid-swirl unbreaks the projects list and cracks open self-hosting

A two-part fix that stops the main projects view from erroring out for real accounts - and lets the fork run on your own storage.

sid-swirl caught a bug where the projects screen returned an error for any user who had an email address on file, which is to say every real account - quietly breaking the primary view people land on. The proposed change corrects how the app queries who a project is shared with, so the list loads instead of failing.

The same work bundles two distinct improvements:

Project sharing that actually loads: the fix repairs the query behind the shared-projects view, so accounts with a populated email see their projects instead of an error.
Bring-your-own storage: it flips a setting so the fork can run against self-hosted or other open, S3-compatible storage backends, not just the hosted default - handy for local development and running your own instance.

Worth noting: the change was proposed but closed without being merged, so the reason it didn't land isn't visible from the outside.