fix: make llm provider async and add tool toggle

.living_spec/stories/04_ollama_model_detection.md

@@ -0,0 +1,17 @@
+# Story: Ollama Model Detection
+
+## User Story
+**As a** User
+**I want to** select my Ollama model from a dropdown list of installed models
+**So that** I don't have to manually type (and potentially mistype) the model names.
+
+## Acceptance Criteria
+*   [ ] Backend: Implement `get_ollama_models()` command.
+    *   [ ] Call `GET /api/tags` on the Ollama instance.
+    *   [ ] Parse the JSON response to extracting model names.
+*   [ ] Frontend: Replace the "Ollama Model" text input with a `<select>` dropdown.
+*   [ ] Frontend: Populate the dropdown on load.
+*   [ ] Frontend: Handle connection errors gracefully (if Ollama isn't running, show empty or error).
+
+## Out of Scope
+*   Downloading new models via the UI (pulling).