Fix git safe.directory error for non-root users after install

The installer runs as root and chowns /opt/pic to the pic user.
Any other user (roof, operator) running make update then hits
"detected dubious ownership". Fix: add /opt/pic to system-wide
git safe.directory after clone, and add same guard in make update.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

install.sh

@@ -247,6 +247,9 @@ fi
 
 # Ensure the pic user owns the directory
 chown -R "${PIC_USER}:${PIC_USER}" "$PIC_DIR"
+# Allow any user to run git commands in this directory (installer runs as root,
+# operators run as themselves — git safe.directory prevents ownership errors)
+git config --system --add safe.directory "$PIC_DIR" 2>/dev/null || true
 
 # ---------------------------------------------------------------------------
 # Step 5 — Run make install