feat(cli): implement DX-first KSeF CLI with docs and tests

[smekcio]

Summary

• implement a new DX-first ksef CLI surface (init, profile, auth, health, invoice, send, upo, export)
• remove implicit fallback to demo for business commands and require explicit/active profile with clear config errors
• add secure token storage and fallback handling improvements (keyring/encrypted/plaintext guardrails)
• improve resilience in config handling, retry/circuit-breaker policy usage, and ZIP path safety
• add comprehensive CLI test suite (unit/integration/smoke) and CLI documentation

Testing

• .\.venv\Scripts\python.exe -m ruff check src/ksef_client/cli tests/cli src/ksef_client/utils/zip_utils.py
• .\.venv\Scripts\python.exe -m mypy src/ksef_client/cli src/ksef_client/utils/zip_utils.py
• .\.venv\Scripts\python.exe -m pytest -q tests/cli