Align CI with the validated Ubuntu support floor

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.

docs/portable-install.md

@@ -15,6 +15,11 @@ Download published bundles, checksums, and release notes from
 - System CPython `3.10`, `3.11`, or `3.12`
 - Runtime dependencies installed from the distro package manager
 
+Current automated validation covers Ubuntu CI on CPython `3.10`, `3.11`, and
+`3.12` for unit/package coverage, plus a portable install and `aman doctor`
+smoke path with Ubuntu system `python3`. The other distro-family instructions
+below remain manual validation targets.
+
 ## Runtime dependencies
 
 Install the runtime dependencies for your distro before running `install.sh`.
@@ -22,7 +27,7 @@ Install the runtime dependencies for your distro before running `install.sh`.
 ### Ubuntu/Debian
 
 ```bash
-sudo apt install -y libportaudio2 python3-gi python3-xlib gir1.2-gtk-3.0 libayatana-appindicator3-1
+sudo apt install -y libportaudio2 python3-gi python3-xlib gir1.2-gtk-3.0 gir1.2-ayatanaappindicator3-0.1 libayatana-appindicator3-1
 ```
 
 ### Arch Linux