Removed the local package-repository serving layer from the CI debian install and docker image build paths. Mina debian packages are now installed directly from the locally-staged .deb files via apt-get (which still resolves non-mina system dependencies from the OS apt sources). install.sh now hands apt absolute .deb file paths so they are not misparsed as `package/release` selectors; the daemon docker image installs the network-config deb only for non-lightnet builds (the lightnet generic package is self-contained and ships no config deb); and the automode transition test re-marks the prefork/postfork sub-packages as auto-installed so `apt-get autoremove` reclaims them as it did under the repo-based flow.
