build: Downgrade unsloth and unsloth zoo (#602)

Author: vivekkalyan

pyproject.toml

@@ -22,8 +22,8 @@ backend = [
     "peft>=0.14.0",
     "hf-xet>=1.1.0",
     "bitsandbytes>=0.45.2",
-    "unsloth==2026.2.1",
-    "unsloth-zoo==2026.2.1",
+    "unsloth==2025.12.9",
+    "unsloth-zoo==2025.12.7",
     "torch>=2.8.0",
     "torchao==0.15.0",
     "accelerate==1.7.0",