feat: support KVS.listKeys() prefix and collection parameters

[barjin]

Adds prefix and collection parameters to the KVS.forEachKey() interface and implements the prefix filter in the MemoryStorage implementation of KVS. Note that MemoryStorage doesn't currently support the collection parameter (it's noop).

Closes #2974

[Copilot]

Pull Request Overview

This PR adds new parameters, prefix and collection, to the KeyValueStore.forEachKey interface and implements prefix filtering in the MemoryStorage implementation.

• Added tests to validate prefix filtering in forEachKey.
• Updated type definitions in storages.ts to include the new parameters.
• Modified MemoryStorage and core KeyValueStore implementations to process prefix and collection parameters (with collection remaining a noop).

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
test/core/storages/key_value_store.test.ts	New tests added to verify prefix functionality and updated mock expectations
packages/types/src/storages.ts	Extended interface definitions to include prefix and collection
packages/memory-storage/src/resource-clients/key-value-store.ts	Added prefix filtering logic and updated pagination based on filtered items
packages/core/src/storages/key_value_store.ts	Propagated the new parameters to listKeys and recursive calls

Comments suppressed due to low confidence (1)

packages/memory-storage/src/resource-clients/key-value-store.ts:160

• Consider updating inline documentation to clarify that the 'count' and pagination values are based on the filtered results when a prefix is provided.

const filteredItems = items.filter((item) => !prefix || item.key.startsWith(prefix));