[Corn Flakes] Rust fix flaky test: ensure generate_random_even_number returns even numbers

[Copilot]

Acknowledging your requirement: concise, high-density, scan-friendly PR description.

test_generate_random_even_number_is_even in Rust was persistently flaky because generate_random_even_number could occasionally return odd values. This change removes that behavior so the function contract is deterministic: always even, always within 0..=100.

• Root cause removed

  • Deleted the 5% mutation path that incremented an even value into an odd value.

• Behavior contract clarified

  • Updated function documentation to reflect guaranteed even output.

• Implementation

  • generate_random_even_number now directly returns an even value from the generated range:

  pub fn generate_random_even_number(&mut self) -> i32 {
      self.rng.random_range(0..51) * 2
  }