Negative follower counts cause whackiness

[realRobotix]

Please confirm the following.

• I checked the existing issues for duplicate problems
• I have tried resolving the issue using the support portal

Describe the bug

Negative follower counts can be stored in the db causing all kinds of whackiness due to different types being used in different places and unsafe type conversion. Might be caused by the project being inherited but i wasn't yet able to further dig into that.
first discovered here

db uses integer

database/models/project_items.rs uses i32

models/v2/projects.rs uses u32 (unsafe conversion happens here)

models/v3/projects.rs uses u32 (and also here)

models/v2/search.rs uses i32

Steps to reproduce

1. Go to https://modrinth.com/modpack/advanced-optimized-official
2. Take a look at the follower count (u32::MAX)
3. Go to https://modrinth.com/modpacks?s=follows&m=1&page=8040 or the last page with sort set to followers
4. Take another look at the follower count (-1i32)

Expected behavior

No negative follower counts

Additional context

No response

[realRobotix]

I'm also not too sure why followers are saved in two locations. I feel like the better approach would be just to use COUNT on the mod_follows table (maybe with some caching if it's too inefficient). https://github.com/modrinth/code/blob/main/apps/labrinth/src/routes/v3/projects.rs#L2211-L2229

[imheavi]

The database probably stores a follow count for each project, as well as the total follow count for an account, hence why there are too. Possible I'm wrong however.

[realRobotix]

no, the follows relation is stored in the mod_follows table consisting of the user id and mod id. so far so good...
but there is also a follow count in the mod table which isn't being handled in the same way (e.g. no subtraction of followers on account deletion while all mod_follows relations of the account get deleted) this might be intended behavior to not influence follower counts when a user deletes their account but on first sight this looks like a bad practice