feat(ui): render the scene sharing dialogs and bar from a store

createSceneDialog keeps its builder but publishes the dialog's lines,
fields, buttons and status to a scene sharing store; SceneDialog.vue,
teleported to the body from the scene panels view, draws the same modal
with the same styles and opens it with Cancel focused. The EDIT DETAILS /
SHARE SCENE bar is drawn by that view while sharing offers it. The status
directive is shared with Provider Settings, and the two QA scripts that
drove the old DOM read the new dialog.

docs/APPLICATION.md

@@ -205,8 +205,9 @@ Provider Settings. A page places each Vue view in `src/ui/views` with a host,
 screen (`#loading-screen` with a `.loader-status` line) as static markup so it
 paints before any script runs. `createApplication()` renders the views before
 anything reads the page; `omitViews` names views the application leaves out,
-such as `provider-settings`, and their hosts are removed. An unknown view name
-is an error. A host that does not initialize Core's locale passes
+such as `provider-settings`, and their hosts are removed. Leaving out
+`layer-panels` also leaves out the scene sharing dialogs it draws. An unknown
+view name is an error. A host that does not initialize Core's locale passes
 `localePicker: false` to `createApplicationControls` instead of editing the
 markup. Node tests that import application modules register the component
 loader with `node --import=<core package>/build/register-vue`.