An apt autoremove on Ubuntu 26.04 purged python3.12, so the receiver
venv's bin/python3 -> /usr/bin/python3 silently resolved to python3.14
and all four platform services crash-looped on 'No module named
uvicorn' while state.json still looked healthy.
The venv is now pinned to a uv-managed CPython 3.12.3 (pydantic 1.10.2
breaks on >=3.12.4 via ForwardRef._evaluate), which is not a dpkg
package, so add a guard that verifies interpreter version, base_prefix,
core dependency imports, and service restart counts. Includes a
negative-test suite proving the guard fails on real breakage.
root
c3123fd0b2