Address review: playable PLAY/NEXT, visible rename editor, accurate copy

- PLAY and NEXT continue into the following scenes, so they stay
  enabled while any scene in the project has a shot, not only the
  selected one.
- Renaming a shot drops the number and ellipsis so the editor is no
  longer hidden; qa-scene-controls checks a long rename stays visible.
- PLAY, NEXT, EDIT DETAILS and SHARE SCENE tooltips describe what the
  buttons do, translated in every shipped language.
- The primary actions and the file row keep a hover state.
- Docs: the EXPORT rename in DIRECTOR-SHARING and the playback button
  states in CURRENT-STATE are accurate.
- Test the voice "authoring" alias through set_panel_open.

src/ui/sceneControls.js

@@ -220,7 +220,11 @@ export class SceneControls {
     const shots = scene?.shots ?? [];
     presentSceneButtons(this.elements, running, state.hasRun, {
       hasScene: !!scene,
-      shotCount: shots.length,
+      // PLAY and NEXT run on into the following scenes.
+      playableShots: (state.scenes ?? []).reduce(
+        (total, item) => total + (item.shots?.length ?? 0),
+        0,
+      ),
       hasSelectedShot: shots.some((shot) => shot.id === state.selectedShotId),
     });
     this.elements.panel?.classList.toggle('has-shots', shots.length > 0);