fix: handle no-body / optional-body endpoints and empty 2xx responses

[Tam2]

Follow-up to #3 (the PATCH/PUT bare-body fix). While wiring the generated client into a real app, several related gotchas surfaced around endpoints that have no request body or an optional one, plus empty successful responses. All are fixed here with tests, including large real-world fixtures.

Fixes

1. Generator: stop requiring a body for no-body endpoints

hasBody was assumed for every POST/PATCH/PUT, so the command schema always emitted a body field. For an endpoint with no request body that's body: never, forcing callers into as any. Now the generator detects the actual requestBody per operation and emits:

• path + body → z.object({ path, body })
• path, no body → z.object({ path })
• no path + body → body-directly
• no path, no body → z.void() (no-argument action command)

Detection resolves operations["Name"] refs against the operations interface, including quoted operationIds like "activity/star-repo-for-authenticated-user" (GitHub/Stripe style).

2. Runtime: don't forward { path } as the request body

buildRequestOptions now resolves the body as hasBody ? input.body : hasPath ? undefined : input, so a path-only input sends params with no body (previously it would have sent { path } as the body).

3. Runtime: empty 2xx responses are success, not 404

handleResponse treated any response with no data as a 404 — breaking 204 No Content and void/action endpoints. It now returns success on an ok response with an empty body, and uses response.status (works for any API) instead of a Nest-specific error.statusCode.

4. Types: GetRequestBody matches optional bodies

It only matched a required requestBody:, so every optional-body operation (requestBody?:) typed to never — 490 such ops in the Stripe fixture, 66 in GitHub. Now matches both required and optional. Verified required + optional resolve correctly via tsc.

Tests

• Unit + generator + type tests for every case above.
• New real-world fixtures: test/fixtures/{stripe,github}.d.ts (api.d.ts from the public Stripe & GitHub OpenAPI specs, ~1,800 endpoints). These caught the quoted-operationId gap and guard against regressions at scale.
• 110 tests pass. CodeRabbit review of src/: no findings.

No version bump — the release workflow handles it.

Note (not fixed here)

The expectTypeOf type tests aren't currently type-checked by vitest run (no typecheck config; tsconfig excludes test/). Worth enabling vitest --typecheck in a follow-up so the type assertions actually run in CI.