Function detectPlugins

Detects the @setu-ts packages a project depends on.

Reads deno.json (its imports map) and, when that is absent or carries no scoped entries, package.json (dependencies + devDependencies). Detection never boots or imports the target project.

JSONC comments and trailing commas are accepted for reads. Writing commands classify the project first and report malformed manifests by path, so an unreadable manifest never turns into a misleading plugin-not-installed gate.