Block showItemInFolder and writeShortcutLink using the shared active shell boundary, preserving undefined/false synchronous refusal contracts and shape-only timeline evidence.
Retain Nitin13-git implementation and add base-red/shared-contract coverage plus a reproducible unchanged Joplin welcome-attachment reveal. Local87cases, static and docs pass. The explicit test argv shim verifies the operation phase; standard startup and provider cleanup remain unsuccessful and are recorded without a full-workflow performance claim.
Fixes#4393
Co-authored-by: Nitin13-git <internshipsvc01@gmail.com>
Co-authored-by: gensokyo-dev <342580529+gensokyo-dev@users.noreply.github.com>
Co-authored-by: Kaoru0822 <208281322+kaoru0822-kitauji@users.noreply.github.com>