[Refactor] Modernize archiver utilities with async/await

[gonzaloriestra]

This PR refactors the archiving utilities in @shopify/cli-kit to follow modern asynchronous patterns.

Why:

The previous implementation used manual Promise wrappers and .then() chains which were more verbose and harder to reason about. Moving to async/await makes the control flow clearer, especially when coordinating multiple asynchronous operations like globbing, file reading, and stream finalization.

Changes:

• zip: Now uses async/await for globbing and file addition. It waits for archive.finalize() and the output stream's close event before resolving.
• brotliCompress: Similarly modernized to use async/await for the internal tar archive creation step.
• Documentation: Added @returns to zip JSDoc.

How to test your changes?

CI. (Integration tests in packages/cli-kit/src/public/node/archiver.integration.test.ts cover these changes).

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PR created automatically by Jules for task 2020363541973881611 started by @gonzaloriestra

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[github-actions]

Differences in type declarations

We detected differences in the type declarations generated by Typescript for this branch compared to the baseline ('main' branch). Please, review them to ensure they are backward-compatible. Here are some important things to keep in mind:

• Some seemingly private modules might be re-exported through public modules.
• If the branch is behind main you might see odd diffs, rebase main into this branch.

New type declarations

We found no new type declarations in this PR

Existing type declarations

packages/cli-kit/dist/public/node/archiver.d.ts

@@ -18,6 +18,7 @@ interface ZipOptions {
  * Windows.
  *
  * @param options - ZipOptions.
+ * @returns A promise that resolves when the directory has been zipped.
  */
 export declare function zip(options: ZipOptions): Promise<void>;
 export interface BrotliOptions {