test: raise coverage to 100% and fix lint in tests

[smekcio]

Summary

• raise project test coverage to 100% (line + branch)
• close previously uncovered branches in CLI, SDK adapters, clients, models, services and utility modules
• fix lint issues introduced by new coverage tests

Changes

• Added and expanded tests across:
  • CLI integration/unit (init, auth manager, config profiles, human output, SDK adapters)
  • Core SDK modules (clients, http, crypto, models, openapi_models, base64url, zip_utils)
  • Service layer workflows (csr, person_token, workflows)
• Added explicit branch-path assertions for optional/empty inputs and fallback/error paths
• Refactored long assertions/patch blocks in tests to satisfy Ruff line-length and import rules
• Kept production code behavior unchanged (test-only + lint-only adjustments)

Validation

• python -m pytest -q
• Result at submission time: 503 passed, 4 skipped, 1 warning
• Coverage: TOTAL 100% (line + branch)
• python -m ruff check .
• Result: All checks passed!