feat: return user and chat errors in API response (AssemblyScript)

[mattjohnsonpint]

This continues on the work in #863, implementing for the AssemblyScript SDK.

There are a couple of minor differences:

• Errors that are thrown via throw new Error(...) will continue to be logged but not emitted via the GraphQL API, because they're likely not intended to be user facing. (In the future we will be able to catch these via try-as.)
• User-facing error messages can be thrown via utils.throwUserError(...), which logs the error and exits cleanly. The runtime will trap this error message and return it via the GraphQL API errors section.

[trunk-io]

Running Code Quality on PRs by uploading data to Trunk will soon be removed. You can still run checks on your PRs using trunk-action - see the migration guide for more information.

[Copilot]

Pull Request Overview

This PR adds support for returning user-facing and chat model errors in the AssemblyScript SDK’s GraphQL API response.

• Hooks a validator into the chat model invocation to parse and throw user errors.
• Implements validateChatModelResponse and a new ChatModelError type for parsing API error payloads.
• Adds throwUserError utility and updates Model base class to exit cleanly on user errors.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
sdk/assemblyscript/src/models/openai/chat.ts	Added validator assignment, validateChatModelResponse, and ChatModelError.
sdk/assemblyscript/src/assembly/utils.ts	Introduced resultIsInvalid and throwUserError utilities.
sdk/assemblyscript/src/assembly/models.ts	Extended Model with validator hook and user-error exit logic.
CHANGELOG.md	Updated changelog entry to include this PR (#864).

Comments suppressed due to low confidence (2)

sdk/assemblyscript/src/models/openai/chat.ts:1593

• The new validateChatModelResponse function and its branches (empty response, error payload, normal path) lack unit tests. Adding tests will help ensure that future changes don't break these error-handling paths.

function validateChatModelResponse(data: string): ModelError | null {

sdk/assemblyscript/src/assembly/models.ts:102

• The utils namespace isn't imported in this file, so utils.throwUserError will be undefined. Add or correct the import for the throwUserError function from utils.ts.

utils.throwUserError(`The chat model returned an error: ${err}`);