feat(player): the YouTube player and the file viewer are named in the address

The player names what it plays in its own history entry (watch, wrel, wtab): a reload or a
bookmark reopens it on the page that hosts it, with that page's list as the queue, or alone
from the catalog (GET /api/videos/{id}/row); a page that hosts none gets the shell's. Back
lands on the page's address without it (useBackToClose's url; ui/Modal passes it on). The
Files viewer and player do the same (fview, fplay). The Plex and channel-manager views are
always written in full, as their fallback is remembered state.

frontend/src/modules/home/module.ts

@@ -14,4 +14,5 @@ export const homeModule: ModuleDef = {
   // Nothing of its own: the question is an answer, not a setting — the same question draws other
   // cards once what you have watched moves on.
   urlKeys: [],
+  playsVideos: true,
 };