Address Review Comments on PR

Link to Pull Request address the review comment on the branch

Changes:

• --search-skill in non-interactive mode with no enabled agents now prints targeted install guidance.
• It exits with a SilentError instead of silently succeeding.
• Added unit coverage for the guidance/error path.

Tested:

• go test ./cmd/entire/cli

Pushed Commit:

• 69a50e4bc Guide non-interactive search skill install

Commit Link