v0.1.2 — default to GLM-5.1

Claudia Router v0.1.2 switches the default NVIDIA routing path to z-ai/glm-5.1, which gives the router a much larger context window and makes long Claude Code prompts more reliable. The release keeps the GLM, Qwen, and smoke-test presets available as explicit alternatives, with clearer documentation of their tradeoffs. It also improves context-overflow handling so the router gives a clearer error when the prompt itself is too large for the selected model.