[Tests] Remove filesystem mocks in bundle-ui-step.test.ts

[gonzaloriestra]

WHY are these changes introduced?

Filesystem mocks in tests prevent verifying actual filesystem side effects and can lead to implementation-coupled tests that don't catch real-world path handling issues.

WHAT is this pull request doing?

Refactors `packages/app/src/cli/services/build/steps/bundle-ui-step.test.ts` to replace global `vi.mock('@shopify/cli-kit/node/fs')` with real filesystem operations using `inTemporaryDirectory`. It uses `mkdir` and `writeFile` to set up the test environment and `fileExists` to verify the success of `copyFile`.

How to test your changes?

CI

Post-release steps

N/A

Checklist

• I've considered possible cross-platform impacts (Mac, Linux, Windows)
• I've considered possible documentation changes
• I've considered analytics changes to measure impact
• The change is user-facing — I've identified the correct bump type (`patch` for bug fixes · `minor` for new features · `major` for breaking changes) and added a changeset with `pnpm changeset add`

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PR created automatically by Jules for task 18014390488825622297 started by @gonzaloriestra

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[craigmichaelmartin]

See test comments

[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/private/node/ui/components/AutocompletePrompt.d.ts

@@ -20,13 +20,6 @@ export interface AutocompletePromptProps<T> {
     abortSignal?: AbortSignal;
     infoMessage?: InfoMessageProps['message'];
     groupOrder?: string[];
-    /**
-     * Throttle window in milliseconds applied to the search callback. Defaults to 400ms,
-     * which is appropriate for remote/paginated backends. In-memory consumers (where the
-     * search callback resolves synchronously) can pass 0 for instant filtering on every
-     * keystroke.
-     */
-    searchDebounceMs?: number;
 }
-declare function AutocompletePrompt<T>({ message, choices, infoTable, onSubmit, search, hasMorePages: initialHasMorePages, abortSignal, infoMessage, groupOrder, searchDebounceMs, }: React.PropsWithChildren<AutocompletePromptProps<T>>): ReactElement | null;
+declare function AutocompletePrompt<T>({ message, choices, infoTable, onSubmit, search, hasMorePages: initialHasMorePages, abortSignal, infoMessage, groupOrder, }: React.PropsWithChildren<AutocompletePromptProps<T>>): ReactElement | null;
 export { AutocompletePrompt };
\ No newline at end of file