feat: align MCP retrieval contract with ra-h

- add external retrieval and confirmation-gated writeback tools across MCP surfaces
- port direct-search-first retrieval support and supporting ranking/query updates
- update MCP docs and skills to treat agent memory files as optional reinforcement

Generated with Claude Code

apps/mcp-server-standalone/services/nodeService.js

@@ -114,6 +114,16 @@ function getNodes(filters = {}) {
   return rows.map(mapNodeRow);
 }
 
+/**
+ * Search nodes using the same filter object as getNodes.
+ */
+function searchNodes(filters = {}) {
+  if (typeof filters === 'string') {
+    return getNodes({ search: filters });
+  }
+  return getNodes(filters);
+}
+
 /**
  * Get a single node by ID.
  */
@@ -316,6 +326,7 @@ function getContext() {
 
 module.exports = {
   getNodes,
+  searchNodes,
   getNodeById,
   createNode,
   updateNode,