Stream delimited output and render terminal-aware tables

[codeforester]

Summary

• stream CSV and TSV rows directly from one-pass iterables
• make redirected output deterministic and free of headers, footers, and terminal control sequences
• make terminal tables Unicode-width-aware with bounded cells and terminal-width fitting
• document the output contracts and add large-generator and TTY/non-TTY coverage

Closes #65

Verification

• .venv/bin/python -m pytest -q
• .venv/bin/python -m mypy lib/python/base_cli/output.py --ignore-missing-imports