test: boost coverage and stabilize CI test env

[Patrik652]

Summary

• publish release hardening for CI by running pytest via python module and setting PYTHONPATH in workflow
• add unit tests for logging configuration and vision service wiring in /vision command setup
• add image processor branch tests for png/webp privacy flow, resize path, and hash error wrapping

Verification

• . ./.venv/bin/activate && ruff check src/services src/cli tests/unit/test_logging_config.py tests/unit/test_vision_command_service_factory.py tests/unit/test_image_processor_branches.py tests/unit/test_screenshot_capture_factory.py
• . ./.venv/bin/activate && mypy src/services src/cli
• . ./.venv/bin/activate && PYTHONPATH=. pytest -q