fix: stop pip's patchelf 'ERROR' line from polluting sosetup.log

The cmd.run for psycopg2 install was already tolerating pip's
non-zero exit with `|| true`, but pip's stderr — which contains the
literal string "ERROR: Could not install packages due to an OSError:
[Errno 2] No such file or directory: 'patchelf'" — was still being
captured into salt's state-result dict. so-setup logs salt state
output to /root/sosetup.log, and verify_setup() then greps for the
substring "ERROR" to build /root/errors.log. The patchelf line then
shows up at the end of every install as "WARNING: Errors detected
during setup" even though the install is in fact green.

Redirect pip's combined stdout/stderr to
/opt/so/log/so_pillar/psycopg2_install.log so the noise lives in a
dedicated, predictable triage location instead of leaking into salt's
state result. The `unless: import psycopg2` check is still the
actual readiness gate, so a real install failure (rather than just
the patchelf RPATH-rewrite step that has no functional effect on the
wheel) would still surface via the state being re-run on every apply
and `import psycopg2` failing.

salt/postgres/schema_pillar.sls

@@ -123,9 +123,19 @@ so_pillar_role_login_passwords:
 # installed and importable. salt's pip.installed surfaces the non-zero exit
 # as a state failure and the cascade kills schema_pillar's downstream work.
 # `import psycopg2` succeeds either way, so that's the actual readiness gate.
+#
+# Pip's stdout/stderr is redirected to /opt/so/log/so_pillar/psycopg2_install.log
+# so the literal "ERROR: ... patchelf" line doesn't get hoovered up into
+# /root/sosetup.log and then into /root/errors.log by verify_setup's
+# substring-grep for "ERROR". The redirect target is preserved for
+# triage if `import psycopg2` ever does fail.
 so_pillar_psycopg2_in_salt_python:
   cmd.run:
-    - name: /opt/saltstack/salt/bin/pip3 install --quiet psycopg2-binary || true
+    - name: |
+        mkdir -p /opt/so/log/so_pillar
+        /opt/saltstack/salt/bin/pip3 install --quiet psycopg2-binary \
+          >/opt/so/log/so_pillar/psycopg2_install.log 2>&1 \
+          || true
     - unless: /opt/saltstack/salt/bin/python3 -c "import psycopg2"
     - require:
       - cmd: so_pillar_role_login_passwords