fix(file-manager): expose selected-item actions on touch devices

[csells]

Summary

• add a persistent selected-item action bar for compact and coarse-pointer File Manager layouts
• open the complete action set in the existing responsive bottom drawer
• disable native row and tile dragging on touch-oriented surfaces, avoiding the long-press drag ghost
• keep desktop right-click menus and native dragging unchanged
• derive desktop and touch actions from one shared model and one panel wiring path

Why

On mobile, long-pressing a File Manager row started browser drag mode instead of exposing useful actions. Selected files and folders therefore had no discoverable way to rename, move, copy, delete, download, or add to chat.

The interaction now also covers wide coarse-pointer layouts such as landscape phones and tablets.

Verification

• npx vitest run test/frontend/menus.test.tsx test/frontend/gallery.test.tsx test/frontend/dragdrop.test.tsx test/frontend/selection.test.tsx --reporter=dot --maxWorkers=2 — 66 passed
• npx vitest run test/frontend/bookmarks.test.tsx --reporter=dot --maxWorkers=2 — 16 passed
• npm run typecheck
• npm run types:check
• npm run build
• manually verified from a phone against a live bb installation

[csells]

@xMinor-1, when you have a chance, could you please review this mobile File Manager fix? It has been verified on a phone against a live bb installation, and the focused tests, type checks, and build all pass.