fix: cli config error handling

[avallete]

Changes

• Split rootPath from packageJsonPath basically, since we can now local the config somewhere else via --config option, we want to search for the closest seed.config.ts first, then, for a package.json as fallback for the root folder.
• Fix double error messages when command throw errors, we basically handled the failure twice before instead of doing it once.
• Fix command spinner not always cleanly stopping when exception was throwed
• Fix npx tsx ./folder/seed.mts and npx @snaplet/sync --config ./folder/seed.config.ts sync
• Early and cleanly exit the sync by throwing error if we see that we won't be able to generate because missing config file/folders
• Fix sync ensure that the user is logged in before running (I'm not sure this is correct, maybe we should just skip all the "prediction/api related" stuff in that case ?)
• Make sure ensureDotSnapletPath does actually create the folder if it doesn't exist

Several users has been reporting error with the config in the cli. Those errors weren't very explicit, this is an attempt at making them more explicit, and more controlled. It also fixes some bugs.

https://www.loom.com/share/6051e974d8cc47c8bcac8cb3658f974c

[justinvdm]

Didn't review code, but UX changes in PR description sound good to me