dsh-bigmodel-catalog: Enable DeepSeek Harness to use Zhipu GLM Coding Plan and glm-5.3

`opensaozi/dsh-bigmodel-catalog` is a DSH (DeepSeek Harness) model catalog plugin used to integrate Zhipu BigModel / GLM Coding Plan into the DSH model selector. It is maintained by OpenSaozi under the MIT License, with the npm package name `@deepseek-ai/dsh-model-catalog-bigmodel`. Core features include unlocking the 1M context window and 128K max output for glm-5.3, and supporting glm-4.5, glm-4.6, and glm-5; it connects to the Zhipu Coding PaaS endpoint to enable real-time catalog reconciliation, with glm-5.3 retained as a verified exception. The plugin registers an independent zai adapter.