Refactor API integration and enhance command handling

- Removed unused modules and updated module paths for clarity.
- Added autocomplete functionality for command input in InputState.
- Updated AppStateRest to include a method for checking if a turn is in flight.
- Refactored subagent engine to use new API client structure.
- Changed default provider from "openrouter" to "zen" with updated API keys and models.
- Implemented tests for memory management and edit log functionalities.
- Enhanced error handling in API requests and improved response parsing.
- Updated UI components to reflect new API provider and status indicators.

src/model/settings.rs

@@ -45,8 +45,8 @@ impl Default for Settings {
     fn default() -> Self {
         Settings {
             internet_mode: InternetMode::Off,
-            provider: "openrouter".to_string(),
-            model: "anthropic/claude-opus-4-8".to_string(),
+            provider: "zen".to_string(),
+            model: "deepseek-v4-flash-free".to_string(),
             api_key: None,
             max_tokens: 8192,
             temperature: 0.7,