Improve planner mode user experience with better error reporting,
cleaner tool output, and consistent log file placement.
- Propagate and display classified LLM errors to users with
appropriate icons and context
- Display tool calls on single lines with truncated arguments
- Show LLM text responses without overwriting via UiWriter
- Ensure all logs write to workspace/logs directory consistently
- Set G3_WORKSPACE_PATH early in planning mode initialization
