feat(commit-with-llm): dynamically detect default LLM model and remove explicit model flag

bin/commit-with-llm

@@ -17,8 +17,8 @@ $(git diff --staged)
 EOF
 
     # Run the llm command
-    echo -e "Send prompt with staged git diff and wait for the response of the $LLM_MODEL LLM."
-    RESULT=$(cat "$PROMPT_FILE" | llm -m "$LLM_MODEL")
+    echo -e "Send prompt with staged git diff and wait for the response of the  $(llm models | sed -n 's/^Default: //p') LLM."
+    RESULT=$(cat "$PROMPT_FILE" | llm)
 
     # Check if result is empty
     if [ -z "$RESULT" ]; then