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

test/package/db-tool/test/help.sh

@@ -0,0 +1,19 @@
+# shellcheck shell=dash
+
+HECTIC_NAMESPACE=test-db-tool-help
+
+log notice "test case: database --help exits 0"
+if ! database --help > /tmp/help-out.txt 2>&1; then
+  log error "test failed: database --help exited non-zero"
+  exit 1
+fi
+
+for tok in deploy pull_staging cleanup check log init migrator; do
+  if ! grep -qF "$tok" /tmp/help-out.txt; then
+    log error "test failed: --help output missing token: $tok"
+    cat /tmp/help-out.txt >&2
+    exit 1
+  fi
+done
+
+log notice "test passed"