docs(vectorstore): add examples/minimal/config.yaml (#7)

Follow-up to workflow#714.

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: intel352

examples/minimal/config.yaml

@@ -0,0 +1,13 @@
+# Minimal config exercising workflow-plugin-vectorstore.
+# Schema-validate with: wfctl validate --skip-unknown-types examples/minimal/config.yaml
+version: 1
+modules:
+  - name: vectorstore-provider
+    type: vectorstore.provider
+    config: {}
+workflows:
+  pipeline:
+    steps:
+      - name: example
+        type: step.vector_upsert
+        config: {}