UI.25 One state language: an action enables or disables menu items, shows and updates panels, and selects on the canvas; every unit follows the same state

Owner 2026-11-09: "remember that actions can enable or disable menu items or make panels show/update as well as selecting objects on the canvas." What exists: every app wires this by hand in its own code: Properties refreshes on the app's selection event, the project tree selects through app code, the command registry (ccInput) knows commands but no enabled or visible condition, menus and toolbars are static until an app toggles classes, contextual ribbon tabs do not exist (UI.11), Problems and the add-ons read their own events. Change: (1) one state in the shell (ccState): selection (ids, kinds, count), mode (model / paper, 2D / 3D), the active view, the current layer and tool, document dirty; the apps publish into it through the host adapter; nothing else writes it; (2) declarations as data: a command, menu item, button, ribbon tab or panel says when it is enabled, visible or shown (enabled: selection.count > 0; visible: selection.kind == wall; show: problems.count > 0) in the registry and the layout file (format v2), never in per-app DOM code; the dock manager applies them: items dim, contextual tabs appear and go (UI.11), panels show or refresh, badges count; (3) the reverse channel: a unit acts on the canvas through the host (select, reveal, highlight), so a Browser row, a Problems line, a schedule row or a search hit selects and zooms to the objects with the same undoable selection the pointer makes; (4) one action path: every button, menu item and shortcut runs the registry command, so one command in a ribbon, a palette, a menu and the status bar has one enabled state and one label; (5) a check (bin/test-shell-state.mjs) opens every app, selects through the host and asserts Modify enabled, Properties updated, the Browser row lit, a declared contextual tab shown, then selects from the panel and asserts the canvas selection. The mockup's demo shows the behaviour (click a wall, or its Browser row). SuperCad Studio's host is the same contract.