Summary

• Add --void-type option to infer command to control how void types are rendered in TypeScript (undefined vs null)
• Make --lang optional for infer - type generation now works with unlinked queries
• Fix emission of entrypoints with primitive result types (like VOID)

Changes

TypeScript codegen (typegen/typescript.rs):

• Add VoidType enum (Undefined | Null)
• Add void_type field to Config
• Fix collect_reachable_types to properly emit entrypoints with primitive result types

CLI (plotnik-cli):

• Add --void-type <TYPE> argument (accepts null, defaults to undefined)
• Make --lang optional - infer now works without a language by emitting from unlinked queries

Test plan

• make clippy passes
• make test passes