Enumerate forks programmatically

Right now, forks and their schedules are typically struct fiends. This results in a schema change every time a fork is added, which requires tedious, error-prone updates across the codebase.

We should only have to update a line or two in a single file to add a fork and its metadata (or perhaps only the superchain registry, in an ideal world).

Start by tracing where fork schedules and their metadata are represented as struct fields across the codebase. Identify the central registry or single file that could own this information, then verify the affected consumers. Done means adding a fork requires only a line or two in one place without schema changes or repetitive updates elsewhere.

Written by the indexing model from the issue text.