install.sh creates a --system-site-packages venv (so it can still see
the system-installed PyGObject bindings, which pip can't build
reliably) and pip-installs the rest of requirements.txt into it.
Checks for PyGObject (GTK4 + libadwaita) and tesseract up front and
prints per-distro package hints if either is missing, rather than
failing deep into pip install. run.sh now prefers .venv/bin/python3
when it exists, falling back to system python3 otherwise. README gets
an Install section describing this.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
