max / quasi

Give a region row's members a Width, and retire the kinds it said Max's ruling on quasicoherent `b1d4c5d7`, built as `cf981aaa`. `Ranked` gains a `layout::Width` beside its `Priority`, so a row can say how the room is divided while there is enough of it as well as what goes first when there is not. `Column` has said both since it existed; a region row could say only one. `RegionKind::Split` and `RegionKind::Columns` are gone. Both were arrangement spelled as containment: they said nothing about scroll, depth or what may be inside, only how the room is divided. A run says it and says more, because the row also carries a `Fallback` and can state what happens when the room runs out, which neither variant could. Split is content then fill; Columns is a row of fills, which divide equally by that type's own rule. `Sidebar` was measured with them and stays. It marks which region is the side of a `SidebarContent` screen, which quasi-tui and quasi-immediate both match on to place it, and no width on a row member can say that. `Band` is a separate judgement and is untouched. `Content` is the default because that is what a run member already drew: a flex item with a min-content floor and no grow, a terminal cell count, an egui galley. So every member written before this keeps its drawing and a screen opts into dividing the room by saying so. All three renderers honour it. The webview writes `data-width` and leans on makeover-webview 0.74's rule; the terminal hands the leftover of a packed line to that line's fills, one cell each for the remainder; egui allocates an equal share of what is left where the member stands, which is exact when the fills follow the members that take what they need. `declare!` grows one production: `beside <priority> [<width>] <emission>`, with the width told from the member by what a member is. Refused on a region's body and on a row of a list, because a stack gives every member the whole width and a list row places its parts by name. Also: a copy loop is told from a hole by the string literal after the word. `copy` is a legal binding and audiofiles has one, which the first landing missed by verifying MNW and this workspace and not the app trees.