docs: improve comments for standalone toolset metadata

- Enhanced field comment to clarify use case
- Added note about additive behavior to SetToolsetMetadata docstring

Co-authored-by: SamMorrowDrums <4811358+SamMorrowDrums@users.noreply.github.com>

Author: Copilot

pkg/inventory/builder.go

@@ -32,7 +32,7 @@ type Builder struct {
 	resourceTemplates []ServerResourceTemplate
 	prompts           []ServerPrompt
 	deprecatedAliases map[string]string
-	toolsetMetadata   []ToolsetMetadata // standalone toolset metadata
+	toolsetMetadata   []ToolsetMetadata // standalone toolset metadata for toolsets without registered tools (e.g., remote-only toolsets)
 
 	// Configuration options (processed at Build time)
 	readOnly        bool
@@ -72,6 +72,7 @@ func (b *Builder) SetPrompts(prompts []ServerPrompt) *Builder {
 // SetToolsetMetadata sets standalone toolset metadata for the inventory.
 // This is used for toolsets that may not have tools registered in this build
 // but should still be recognized (e.g., remote-only toolsets).
+// Any metadata provided here is added to metadata derived from registered tools/resources/prompts.
 // Toolsets with Default: true will be included in default toolsets even if
 // no tools use them. Returns self for chaining.
 func (b *Builder) SetToolsetMetadata(metadata []ToolsetMetadata) *Builder {