docs(r-engine): Update R statistics engine guide v1.6 with structured error handling
- Update execute-code error response format with new fields: error_type, error_line, error_context, console_output
- Document withCallingHandlers for warnings/messages capture in sandbox
- Add error code reference table (E001-E101 + E_EXEC, 20+ pattern matching)
- Document format_agent_error() structured error extraction for CoderAgent auto-repair
- Fix caller description: ReviewerAgent paused, CoderAgent is the actual caller
- Clarify difference between /skills (map_r_error) and /execute-code (format_agent_error) error handling
- Update directory structure descriptions for plumber.R and error_codes.R
Made-with: Cursor
HaHafeng
c681155de2