What problems was I solving

The BigIntNumber codec in @architect/codecs was exported but had no consumers anywhere in the codebase, leaving behind dead code that expanded the package's public API surface without adding value.

What user-facing changes did I ship

None. This is an internal cleanup with no user-visible behavior, schema, or service-contract changes.

How I implemented it

Deleted architect/codecs/main/bigint-number.ts entirely and removed the export * from './bigint-number' barrel re-export from architect/codecs/main/index.ts.

Description for the changelog

Removed the unused BigIntNumber codec and its barrel re-export from @architect/codecs. No callers existed, so this is a non-breaking internal cleanup with no runtime impact.