Investigate implementing iterator based approach for `getMapEntries`

In https://github.com/0xMiden/miden-client/pull/1323, an approach was based for retrieving all entries in a specific storage map. The getter collects into a vector every time.

This will be fine for most storage maps but copying big maps into JS might not be ideal. We could investigate if there is a way to implement an iterator-based approach for this function (and any other that works similarly in the web client right now).

Examine the `getMapEntries` function and similar functions in the web client codebase, likely in storage-related modules. Review the linked pull request #1323 to understand the current vector-based approach. Investigate JavaScript/TypeScript iterator protocols and patterns for streaming large datasets without full in-memory copies. Determine if the underlying storage API supports incremental retrieval.

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