Add opt-in Rich and OpenTelemetry integrations

[codeforester]

Summary

• add isolated rich and telemetry optional extras without core dependency imports
• add opt-in Rich terminal tables with deterministic fallback to the built-in renderer
• emit best-effort OpenTelemetry lifecycle spans/events with safe run metadata
• preserve machine and redirected output contracts and document installation, opt-in, and degradation behavior

Closes #66

Verification

• .venv/bin/python -m pytest -q
• .venv/bin/python -m mypy lib/python/base_cli/integrations.py lib/python/base_cli/context.py --ignore-missing-imports
• git diff --check

The local wheel build could not run because this checkout's virtualenv lacks
the build backend (setuptools.build_meta); CI will exercise distribution
validation in its isolated environment.