VB-Toml to DB migration

[Byron]

I tried Claude to create a plan, by my design constraints didn't really 'stick' with it, so I quckly gave up.
My hope was that I start with a lose spec and refine it once, just to fill this PR with tasks, but it didn't quite work.

Goals

• backward compatibility - we keep writing the toml file, but don't read from it.
• DB-backed versions of RefMetadata and VirtualBranchesHandle
• Update call-sites with new types, they shouldn't notice a difference and it can be done incrementally.

Tasks

• VORM Schema for Toml DB
  • conversion from and original data, keep it simple, probably just a TOML dump
• VirtualBranchesHandle uses DB
• RefMetadata uses DB
  • The plan is to some day get rid of VirtualBranchesHandle, and then migrate to a new schema entirely just for RefMetadata.

[vercel]

@Byron is attempting to deploy a commit to the GitButler Team on Vercel.

A member of the Team first needs to authorize it.