fix(cli): label plugin search as catalog discovery, not web search

[ankitranjan7]

Description

Related to #387. CLI-first; does not close the issue. Skill PR #391 stays separate.

Empty webcmd plugin search looked like a failed web search ({"plugins":[],"errors":[]}). Agents then guessed URLs.

• JSON always includes kind: "plugin-catalog", query, total, and scope.
• Empty JSON adds a hint pointing at webcmd web fetch of a DuckDuckGo HTML results URL.
• Empty table/yaml prints catalog-not-web copy instead of (no data) / [].
• Help text: this command is not web search.
• Local and hosted share plugin-search-presentation.ts.

Type of Change

• 🐛 Bug fix

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• If I edited skill-src/, I ran make build and committed skills/

npx vitest run --project unit src/plugin-search-presentation.test.ts src/cli.test.ts src/hosted/runner.test.ts
275 passed
npx tsc --noEmit

Screenshots / Output

Empty research query:

{
  "kind": "plugin-catalog",
  "query": "tls fingerprint",
  "total": 0,
  "scope": "installable marketplace plugins matched against name and description",
  "plugins": [],
  "errors": [],
  "hint": "webcmd plugin search finds plugins to install, not web pages. For web research: webcmd web fetch --url \"https://html.duckduckgo.com/html/?q=tls%20fingerprint\""
}

[github-actions]

🟠 Maintainer review suggested — low confidence

The automated review could not reach a fully supported conclusion.

This review is advisory and does not block merging.