feat: double-word Array abstraction

[mmagician]

Similar to #2203, but lets the caller get/set double-words in one go with a convenient interface.
Internally, the words are stored under keys [index, 0, 0, 0] and [index, 1, 0, 0] in the storage map.

In the light of having a double-word array, should we also rename the array to single_word_array? (I would probably leave it as-is, I think simple array is descriptive enough)

[Copilot]

Pull request overview

This PR introduces a double-word array abstraction for Miden, enabling storage and retrieval of two words per index through a convenient interface. The implementation extends the existing single-word array pattern by storing words under keys [index, 0, 0, 0] and [index, 1, 0, 0] in the storage map.

Changes:

• Added double_word_array.masm implementing get/set operations for double-word array storage
• Added comprehensive test coverage in test_array.rs to verify double-word array functionality

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
crates/miden-standards/asm/standards/data_structures/double_word_array.masm	New MASM module implementing double-word array abstraction with get and set procedures
crates/miden-testing/src/kernel_tests/tx/test_array.rs	Added test for double-word array get/set operations with initial and updated values

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