fix(openapi): unmarshal HTTP responses from raw JSON text

[ALagoni97]

Why

When an OpenAPI operation's response schema is a primitive (e.g. type: string or type: number), the payload generator emits unmarshal(json: string) which JSON.parses its argument. But the generated HTTP client handed unmarshal the already-parsed value from response.json():

const rawData = await response.json();          // parsed value
const responseData = Module.unmarshal(rawData); // primitive unmarshal expects raw text

For primitive responses this both:

• failed to type-check — Record<any, any> is not assignable to string (TS2345), and
• threw at runtime — JSON.parse on an already-parsed value (SyntaxError: Unexpected token 'h', "hello world" is not valid JSON).

Object/array payloads happened to work because their unmarshal accepts string | object / string | any[].

What

Hand unmarshal the raw JSON text via JSON.stringify(rawData):

const rawData = await response.json();
const responseData = Module.unmarshal(JSON.stringify(rawData));

Every unmarshal variant accepts a string — object (string | object), array (string | any[]), primitive (string), and unmarshalByStatusCode (any) — so this is uniform across all reply payload kinds. rawData stays the parsed object for the response wrapper's rawData field.

Tests

• New openapi-primitive runtime fixture (test/runtime/openapi-primitive.json + codegen-openapi-primitive.mjs, wired into the runtime generate script) with operations returning a plain string and a plain number.
• primitive-response.spec.ts drives the generated client against a server returning primitive bodies and asserts they unmarshal correctly. This fails before the fix (SyntaxError: ... is not valid JSON) and passes after.
• channels.spec asserts the generated client unmarshals from JSON.stringify(rawData) (and never unmarshal(rawData)), locking in the generation change.
• Full runtime HTTP suite: 16 suites / 128 tests pass; full unit suite: 50 suites / 630 tests pass.

Independent of #387 (auth narrowing) — both touch client.ts but in different regions.

🤖 Generated with Claude Code

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[jonaslagoni]

🎉 This PR is included in version 0.72.8 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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