test/pdda-install-startup-docs.sh: fresh --with-startup-docs install reports 2 errors in the target (want 0)

[noelsaw1]

Symptom

FAIL - a fresh --with-startup-docs install reports zero errors in the target (want '0', got '2')

bash test/pdda-install-startup-docs.sh fails on main.

Pre-existing, not from GH-43

Confirmed by stashing the GH-43 working changes (pdda.sh, pdda-lib.sh,
test/pdda-run-mode-reporting.sh) and re-running: the baseline tree fails identically. Filing
separately so it isn't conflated with that work.

The assertion is about error-level findings in a freshly installed target, which GH-43 does not
touch — it changes only cmd_run's closing line and adds a warn-checks accumulator.

Why it matters

This is the test guarding the GH-23 P2 guarantee that install.sh validates every startup doc it
writes. A fresh install landing 2 errors in the target is either a real install regression or a
drifted fixture, and both are worth knowing — it's the first-run experience for every new adopter,
which GUIDING-PRINCIPLES.md #6 ("cheap to adopt") makes load-bearing.

Note the suite takes >2 min to run, so it is easy to skip in a normal loop and may have been failing
for a while unnoticed.

Next step

Identify the 2 errors (run the installer against a scratch target and diff what it writes vs. what
check_governance expects), then decide whether the fixture or the installer is wrong.