feat(node-sdk): use optimized flag evaluation

[roncohen]

Use the new facility from the flag-evaluation package to ensure low CPU even with huge lists of targets.

[Copilot]

Pull Request Overview

This PR integrates the new optimized flag evaluation facility from the flag-evaluation package to improve CPU efficiency when handling large target lists. Key changes include:

• Removing evaluateFeatureRules mocks and expectations in the test suite.
• Adding a new CachedFeatureDefinition type and integrating newEvaluator in types and client modules.
• Updating client logic to use newEvaluator for both enabled and config evaluations.

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
packages/node-sdk/test/client.test.ts	Removed redundant evaluateFeatureRules mocks and adjusted test expectations.
packages/node-sdk/src/types.ts	Introduced CachedFeatureDefinition and imported newEvaluator to support evaluations.
packages/node-sdk/src/client.ts	Updated feature evaluation flow to compute evaluation results using newEvaluator and adjusted cache type accordingly.