feat(\db-tool\): introduce unified db-tool package with postgres harness and tests (T0-T8)

test/package/db-tool/test/missing-database-dir.sh

@@ -0,0 +1,19 @@
+# shellcheck shell=dash
+
+HECTIC_NAMESPACE=test-db-tool-missing-dir
+
+export PGURL=""
+unset LOCAL_DIR DATABASE_DIR DB_URL 2>/dev/null || true
+
+log notice "test case: database deploy fails without LOCAL_DIR"
+set +e
+database deploy 2>/tmp/missing-err.txt
+code=$?
+set -e
+
+if [ "$code" = 0 ]; then
+  log error "test failed: database deploy exited 0 without LOCAL_DIR"
+  exit 1
+fi
+
+log notice "test passed: exited $code"