fix: properly handle RecipeTag union type in CookbookDetail

- Add name property to RecipeTag interface for backward compatibility
- Add getTagName helper function to extract tag names from union type
- Update tag iteration to use helper function

Fixes TypeScript errors where string | RecipeTag was passed to
string-only contexts.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

packages/shared/src/types.ts

@@ -100,6 +100,7 @@ export interface Tag {
 
 export interface RecipeTag {
   tag: Tag;
+  name?: string; // Optional for backward compatibility with code that accesses .name directly
 }
 
 export interface Cookbook {