add instructions to inventory

Author: tommaso-moro

pkg/inventory/registry.go

@@ -58,6 +58,8 @@ type Inventory struct {
 	filters []ToolFilter
 	// unrecognizedToolsets holds toolset IDs that were requested but don't match any registered toolsets
 	unrecognizedToolsets []string
+	// server instructions hold high-lelvel instructions for agents to use the server effectively
+	instructions string
 }
 
 // UnrecognizedToolsets returns toolset IDs that were passed to WithToolsets but don't
@@ -292,3 +294,7 @@ func (r *Inventory) AvailableToolsets(exclude ...ToolsetID) []ToolsetMetadata {
 	}
 	return result
 }
+
+func (r *Inventory) Instructions() string {
+	return r.instructions
+}