feat: add model checking and conditional pulling for Ollama models

ansible/roles/ollama/defaults/main.yaml

@@ -7,3 +7,4 @@ ollama_host: "0.0.0.0"
 ollama_port: 11434
 ollama_models:
   - qwen3:4b
+  - llama3

ansible/roles/ollama/tasks/main.yaml

@@ -34,8 +34,15 @@
   retries: 10
   delay: 3
 
+- name: Check installed ollama models
+  uri:
+    url: "http://localhost:{{ ollama_port }}/api/tags"
+    return_content: true
+  register: ollama_tags
+
 - name: Pull ollama models
   command: /opt/homebrew/bin/ollama pull {{ item }}
   loop: "{{ ollama_models }}"
+  when: item not in (ollama_tags.json.models | map(attribute='name') | list)
   environment:
     OLLAMA_HOST: "http://localhost:{{ ollama_port }}"