dsh-reasoning-loop-guard: Detecting DSH Reasoning Loops

The `dsh-reasoning-loop_guard` plugin is designed to resolve silent hangs during long-chain inference in DeepSeek Harness (DSH). By monitoring five criteria (such as periodic repetition and k-gram repetition) on the `llm/stream` hook, it can detect repetitive reasoning loops early and interrupt the output, avoiding waste of compute resources. The plugin supports fire alarm logging, the `reasoning_loop_log` tool, and a GUI panel. Installation requires adding the plugin from its GitHub source and enabling it in the configuration file. Note that the desktop version must use the built-in runtime of DSH Desktop, and the plugin only inspects `reasoning-delta` without interfering with normal long-form text output.