Let the shell's share link, HUD, orbit and navigation follow another globe engine

The shell reads its viewer, engine and map stack from the attached scene. ShareLinkManager, IntelHUD and OrbitController gain attachEngine, NavigationController setScene and LocationNavigation attachScene/detachScene, so a switch can keep them and move only their camera listeners; between engines they write and read nothing. The voice runner and session voice modules are owned by their packages, which check:boundaries needs since the voice commit.

scripts/package-boundaries.json

@@ -2660,6 +2660,7 @@
       "src/app/stateChannel.js",
       "src/app/surfaceServices.js",
       "src/app/tools.js",
+      "src/app/sessionVoice.js",
       "src/app/viewer.js",
       "src/sky/starrySky.js",
       "src/sky/stars.js",
@@ -3203,6 +3204,7 @@
       "src/voice/voiceCardPresentation.js",
       "src/voice/resultDisplay.js",
       "src/voice/gevRealtime.js",
+      "src/voice/sceneRunner.js",
       "src/voice/layerSummary.js",
       "src/voice/cloudVoiceAuth.js",
       "src/voice/realtimeBackend.js",