Feature: Search and install flow in CUI

[smota]

Parent epic: #1

Job to be done

When I want new skills, I want to search interactively or by keyword and install selected results with layer and agent choices.

Scope

• CUI search entry for open search and keyword search.
• Display search results using existing skills find behavior.
• Install from selected search result.
• Install from explicit folder, GitHub shorthand, git URL, full URL, or repo tree URL.
• Prompt for layer, defaulting to project.
• Prompt for agents, defaulting to detected agents in the folder.

Implementation notes

• Reuse skills add source parsing and agent detection where possible.
• Standalone mode should call npx skills add with chosen flags.
• Identify whether find needs structured output for reliable CUI result selection.

Acceptance criteria

• Search supports open and keyword flows.
• Install supports search result and manual source input.
• Layer prompt defaults to project.
• Agent prompt defaults to detected agents.