fix llm config for ramalama, add safeguards, spinner animation

- Fix last_narrative -> last_prompt bug in generate() and generate_stream()
- Add **kwargs guard to build_user_message() to catch wrong param names
- Extract _set_llm_env() helper that always sets API key (fallback placeholder)
- Add 30s timeout to all litellm.completion() calls
- Update config model to openai/deepseek-r1 for ramalama
- Replace shifting dots spinner with fixed-character shape morph

session/config.json

@@ -1,8 +1,8 @@
 {
   "llm": {
-    "model": "openai/gpt-4o-mini",
-    "api_key": "not-needed",
+    "model": "openai/deepseek-r1",
+    "api_key": null,
     "api_base": "http://localhost:8080/v1",
-    "temperature": 0.8
+    "temperature": 0.7
   }
 }