[Bug] Skills with same name from different sources not properly namespaced in slash commands

Bug Description
Skills from different sources (plugins, local) with same name are not properly namespaced in slash commands; while multiple completions appear, all completions run the same skill version (e.g. local).

Environment Info

• Platform: linux
• Terminal: tmux
• Version: 2.1.77
• Feedback ID: 2d49a570-1454-46ca-8235-4ac10cdc951e

Reproduction

• create skill "skill-example" in local "~/.claude/skills/"
• create a plugin marketplace with a skill "skill-example" and install the plugin
• try slash commands auto-completion for "/skill" - no namespaced slash command
• try invoking one of the auto-completion - all completion invoke the same skill