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/tool/fs/helpers.rs

@@ -25,3 +25,39 @@ pub fn not_found_help(ctx: &super::super::ToolCtx, path: &Path, rel: &str) -> St
         format!("path '{}' does not exist (resolved to {})", rel, canon.display())
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    #[test]
+    fn test_arg_str_found() {
+        let args = json!({"key": "value"});
+        assert_eq!(arg_str(&args, "key").unwrap(), "value");
+    }
+
+    #[test]
+    fn test_arg_str_missing() {
+        let args = json!({"other": "value"});
+        assert!(arg_str(&args, "key").is_err());
+    }
+
+    #[test]
+    fn test_arg_str_empty_string() {
+        let args = json!({"key": ""});
+        assert_eq!(arg_str(&args, "key").unwrap(), "");
+    }
+
+    #[test]
+    fn test_arg_str_wrong_type() {
+        let args = json!({"key": 42});
+        assert!(arg_str(&args, "key").is_err());
+    }
+
+    #[test]
+    fn test_arg_str_null() {
+        let args = json!({"key": null});
+        assert!(arg_str(&args, "key").is_err());
+    }
+}