Add OpenAI/LiteLLM provider support with settings UI

- Add openai/ provider module with translator, client, convert, request/response translators
- Add shared provider/ types (ConversationMessage, MessageRole, ProviderConfig enum)
- Wire OpenAI-compatible provider dispatch alongside Bedrock in response_stream.rs
- Add ai.openai.* settings (enabled, base_url, api_key, model, models)
- Add OpenAI/LiteLLM settings page with model fetch, picker, and config UI
- Extend model menu items and llms.rs to surface LiteLLM models
- Update WARP.md with OpenAI provider architecture docs

crates/local_inference/tests/e2e_scenarios.rs

@@ -179,7 +179,11 @@ async fn scenario_tab_naming_development_contexts() {
         },
         TabCase {
             label: "Python data science",
-            commands: vec!["jupyter notebook", "pip install pandas", "python analysis.py"],
+            commands: vec![
+                "jupyter notebook",
+                "pip install pandas",
+                "python analysis.py",
+            ],
             cwd: "/home/user/research/data-pipeline",
         },
         TabCase {