Stop implying that one Ubuntu 3.11 unit lane validates the full Linux support surface Aman documents.\n\nSplit CI into an Ubuntu CPython 3.10/3.11/3.12 unit-package matrix, a portable install plus doctor smoke lane, and a packaging lane gated on both. Add a reproducible ci_portable_smoke.sh helper with fake systemctl coverage, and force the installer onto /usr/bin/python3 so the smoke path uses the distro-provided GI and X11 Python packages it is meant to validate.\n\nUpdate the README, release/distribution docs, and Debian metadata to distinguish the automated Ubuntu CI floor from broader manual GA signoff families, and add the missing AppIndicator introspection package to the Ubuntu/Debian dependency lists.\n\nValidate with python3 -m unittest discover -s tests -p 'test_*.py', python3 -m py_compile src/*.py tests/*.py, and bash -n scripts/ci_portable_smoke.sh. The full xvfb-backed smoke could not be run locally in this sandbox because xvfb-run is unavailable.