fix(codegen): preserve equivalent suffixed type references

[rekram1-node]

Summary

Fix Effect client type generation when an encoded schema and a normal optional schema contain equivalent named types.

Schema representation can assign a numeric suffix to one occurrence (for example Message_State_1). The Effect emitter previously only matched exact registered names, so it expanded that occurrence inline instead of preserving the authoritative type reference.

• Retain the generated definition alongside each registered Effect type reference.
• Resolve numeric-suffixed references to the original named type only when their definitions match exactly.
• Preserve distinct definitions that share an identifier.
• Add regression tests for encoded/optional occurrences and conflicting shapes.

This is a standalone generator fix extracted from #48005. It contains only generator implementation and tests; it does not depend on the fork API changes.

Verification

• packages/httpapi-codegen: bun test test/generate.test.ts — 90 passing
• packages/httpapi-codegen: bun typecheck
• packages/client: bun run check:generated — passes without changes to generated baseline files