fix(gxt): swap globalThis.owner per outlet render so engine refinements don't bleed into application

The shared `<ember-outlet>` element calls `tpl.render(nestedContext, this)`
without first swapping `globalThis.owner`. When the nested outlet's owner is
an engine instance (different from the application owner), curly bare
identifiers like `{{ambiguous-curlies}}` resolve via `$_maybeHelper`, which
reads `globalThis.owner` to call `factoryFor('component:...')` — picking up
the application's registry instead of the engine's. A template registered in
BOTH the application and the engine therefore resolved engine-scoped
component refinements against the application owner, leaking application
state into the engine's render output.

Save the previous `globalThis.owner`, swap to the nested outlet's render
owner for the duration of `tpl.render`, and restore it in the finally block.
This matches the analogous swap already present in `gxt-backend/outlet.gts`'s
EmberOutletElement implementation.

Fixes the two failing 'has separate refinements' tests in
`Application test: engine rendering` (20/20 pass; smoke 333/333).

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

Author: lifeart

packages/@ember/-internals/glimmer/lib/templates/outlet.ts

@@ -250,6 +250,20 @@ class EmberOutletElement extends HTMLElement {
       /* ignore */
     }
 
+    // Engine support: when the nested outlet's render owner is an engine
+    // instance (different from the application owner), swap globalThis.owner
+    // for the duration of tpl.render so that $_maybeHelper / $_tag / component
+    // resolution find the engine's registry (e.g. engine-scoped helpers,
+    // components registered only on the engine). Without this swap a shared
+    // template registered in BOTH application and engine would resolve curly
+    // bare identifiers (`{{ambiguous-curlies}}`) against the application owner
+    // even while rendering inside the engine's outlet, leaking application
+    // refinements into the engine's render output.
+    const previousGlobalOwner = (globalThis as any).owner;
+    const ownerSwapped = owner && owner !== previousGlobalOwner;
+    if (ownerSwapped) {
+      (globalThis as any).owner = owner;
+    }
     try {
       if (typeof tpl?.render === 'function') {
         tpl.render(nestedContext, this);
@@ -262,6 +276,9 @@ class EmberOutletElement extends HTMLElement {
         }
       }
     } finally {
+      if (ownerSwapped) {
+        (globalThis as any).owner = previousGlobalOwner;
+      }
       (globalThis as any).__currentOutletState = previousOutletState;
       if (_parentViewPushed) {
         try {