feat(llm): GLM dual-region split + catalog refresh

Zhipu serves GLM under two brands with separate accounts (Z.AI
international vs BigModel China); the CLI URL pointed at one while
the openai_client default pointed at the other. Split into glm +
glm-cn with secondary region prompt (same UX as Qwen + MiniMax).
Catalog adds glm-5-turbo and glm-4.5-air per docs.z.ai.

tests/conftest.py

@@ -18,7 +18,9 @@ _API_KEY_ENV_VARS = (
     "XAI_API_KEY",
     "DEEPSEEK_API_KEY",
     "DASHSCOPE_API_KEY",
+    "DASHSCOPE_CN_API_KEY",
     "ZHIPU_API_KEY",
+    "ZHIPU_CN_API_KEY",
     "MINIMAX_API_KEY",
     "MINIMAX_CN_API_KEY",
     "OPENROUTER_API_KEY",