dsh-is-power-of-two: Power-of-Two Check Utility

`dsh-is-power-of-two` is a DeepSeek Harness (DSH) plugin maintained by uckkk for quickly determining whether a number is a power of two. It is implemented in pure Node.js, has no network dependencies, and provides only standard bitwise validation logic. The installation command is `dsh plugin add github:uckkk/dsh-is-power-of-two`. It requires the `@deepseek-ai/cordis` (^4.0.1) and `@deepseek-ai/dsh-tools` (>=0.1.0-rc.6) dependencies.