[Test] Add unit tests for js/utils/performanceTracker.js

[eyeaadil]

What needs testing

js/utils/performanceTracker.js needs test coverage. It is a utility for performance instrumentation, but currently has no associated tests in the repository.

Current coverage

Current test coverage for this file is 0% (there is no test file).

Proposed approach

I propose creating js/utils/tests/performanceTracker.test.js using the Jest framework to write a comprehensive test suite. The approach will cover:

• Toggling the enabled/disabled state (enable(), disable(), isEnabled()).
• Verifying the "no-op" behavior of tracking methods when the tracker is disabled.
• Testing the timing functions (startRun(), endRun(), getStats(), reset()).
• Testing depth tracking via enterBlock() and exitBlock(), including edge cases.
• Verifying console output logging logic fallback behavior.
• Verifying memory tracking gracefully handles missing performance.memory support in environments like jsdom.

Checklist

• I have read and followed the project's code of conduct.
• I have checked that no existing tests cover this area.
• I have checked that there is no open PR for the tests I am submitting.
• I have reviewed docs/TESTING.md for testing patterns.

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