The tool is registered as `present_files` (plural) in present_file_tool.py,
but four references in documentation and prompt strings incorrectly used the
singular form `present_file`. This could cause confusion and potentially
lead to incorrect tool invocations.
Changed files:
- backend/docs/GUARDRAILS.md
- backend/docs/ARCHITECTURE.md
- backend/packages/harness/deerflow/agents/lead_agent/prompt.py (2 occurrences)