macOS Open panel

PropsPro

The macOS Open panel picking a folder: sidebar, toolbar, folder grid, Cancel / Open.

Works inside a video template; it can't run on its own.

Sidebar (Favorites / Locations / Tags), toolbar with back / forward, view switch, path pop-up and search, a folder grid and Cancel / Open buttons. `select(t, i)` selects a folder at time t; `point(i)` gives the cursor's landing point on it. Runs inside a HyperFrames video template's engine (the `HF` helpers `el` and `tl`, as in ui-walkthrough-launch).