fix: address issues in model pull and chat API

- Refactored model pull logic to improve error handling and user feedback.
- Enhanced chat API to ensure better performance and reliability during message fetching.
- Updated UI components for a more intuitive user experience when interacting with models and messages.

data/models/nemotron.json

@@ -0,0 +1,20 @@
+{
+  "model": "nemotron",
+  "url": "https://ollama.com/library/nemotron",
+  "description": "Llama-3.1-Nemotron-70B-Instruct is a large language model customized by NVIDIA to improve the helpfulness of LLM generated responses to user queries.",
+  "variantsCount": 2,
+  "variants": [
+    {
+      "name": "nemotron:latest",
+      "size": "43GB",
+      "context": "128K",
+      "inputType": "Text"
+    },
+    {
+      "name": "nemotron:70b",
+      "size": "43GB",
+      "context": "128K",
+      "inputType": "Text"
+    }
+  ]
+}