Add deepseek model and use it as default

src/aichat/config.yaml

@@ -3,7 +3,7 @@
 rag_embedding_model: ollama:nomic-embed-text
 rag_chunk_size: 8192
 rag_chunk_overlap: 409
-model: ollama:qwen2.5
+model: ollama:deepseek-r1:7b
 temperature: 0
 clients:
 - type: openai-compatible
@@ -14,6 +14,9 @@ clients:
     - name: qwen2.5
       supports_function_calling: true
       max_input_tokens: 128000
+    - name: deepseek-r1:7b
+      supports_function_calling: true
+      max_input_tokens: 128000
     - name: gemma2
       supports_function_calling: true
       max_input_tokens: 128000