Collections and the project page

I added collections, so projects can be grouped across the board, with assignment from the triage toolbar and an undo. The project page got three tabs, a description drawer, links, a Musical DNA section, and a two-column timeline. Triage now reports how many projects were sorted and skipped. Workspaces are capped at five, with a banner when you get close. I rebuilt the landing sections and added a consent checkbox to sign-up.