fix(staging): ensure wpp can write sqlite db during deploy

infra/staging/deploy_staging.sh

@@ -17,6 +17,11 @@ rm -rf src && mkdir src
 tar -xzf app.tar.gz -C src --strip-components=1
 rm -rf /opt/wpp-staging/app/*
 cp -a src/. /opt/wpp-staging/app/
+# Ensure deploy artifact copied as root does not leave SQLite/app tree non-writable for wpp.
+chown -R wpp:wpp /opt/wpp-staging/app
+if [ -f /opt/wpp-staging/app/db.sqlite3 ]; then
+  chmod 664 /opt/wpp-staging/app/db.sqlite3
+fi
 cd /opt/wpp-staging/app
 runuser -u wpp -- python3 -m venv .venv
 runuser -u wpp -- .venv/bin/pip install -U pip >/dev/null