UI.9: share docking transactions and preserve viewer lifecycle

Preserve legacy selection repair, modifier routing, viewer lifecycle and workspace persistence through the shared docking integration. Qualify the complete workspace gate by refreshing the 18 stale Audio Spectrum hashes for the existing linear renderer, with an independent synthetic-tone regression.

xtask/src/main.rs

@@ -83,7 +83,7 @@ const SAME_LAYER: &[(&str, &str)] = &[
 ];
 
 /// Crates that must not appear below L5 (UI toolkits, windowing, OS audio/menus).
-const UI_ONLY: &[&str] = &["egui", "eframe", "egui-wgpu", "winit", "rfd", "cpal", "muda"];
+const UI_ONLY: &[&str] = &["craft-ui", "egui", "eframe", "egui-wgpu", "winit", "rfd", "cpal", "muda"];
 
 fn short(name: &str) -> &str {
     name.strip_prefix("effectcraft-").unwrap_or(name)