Add GLM-5.2 as a pending model

Zhipu AI's GLM-5.2 listed alongside GLM-5.1 as awaiting a contribution (no
runs yet). Added to both README pending lines.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

models/glm-5-2.json

@@ -0,0 +1,6 @@
+{
+  "label": "GLM-5.2",
+  "vendor": "Zhipu AI",
+  "artifactDir": "glm-5-2/default",
+  "order": 121
+}