refactor: remove retry_count from ProviderConfig and enhance error handling in tool execution

- Removed the `retry_count` field from `ProviderConfig` as it is no longer needed.
- Introduced `argument_error` field in `ToolCall` to capture errors related to tool arguments.
- Updated various components to handle argument errors more gracefully, including in the `ToolDispatcher` and `ConversationOutput`.
- Enhanced tests to validate the new error handling and ensure proper functionality of tool calls.

server/tests/interrupt.rs

@@ -1580,6 +1580,7 @@ fn text_response(text: &str) -> Vec<ModelEvent> {
         ModelEvent::TextEnd,
         ModelEvent::Usage(Usage {
             input_tokens: Some(1),
+            context_input_tokens: Some(1),
             output_tokens: Some(1),
             total_tokens: Some(2),
             ..Default::default()