Two follow-ups on the Firefox lock detection.

A Dock-launched app has launchd's bare PATH, so `python3` could go unfound;
the probe now names `/usr/bin/python3` absolutely first. More importantly,
"held" is now only ever the script's own verdict: a probe that never ran —
no interpreter, or Apple's shim on a Mac without the developer tools, which
exits non-zero after prompting to install — is the probe being unavailable,
not evidence about the lock, and falls back to "not held" rather than
blocking Firefox import on that machine for good. The SQLite snapshot copes
with a live WAL as it does for every other engine.

And `HostProcessAddresses` collected only interface addresses, so a
hostname mapped in /etc/hosts to an address no interface carries — Debian's
127.0.1.1 — read as foreign, holding a crashed Firefox's lock forever. The
set now also includes what the resolver returns for the machine's hostname,
which is exactly what Firefox writes into the lock.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>