Fix release launch crash

[ojowwalker77]

What changed

• stop the sidebar shell's UserDefaults observer from rewriting the layout preference it observes
• make performance-layout persistence idempotent and cover it with a regression test
• add an isolated-profile runtime smoke test to both pull-request verification and the signed release archive
• use Lua consistently as the bundle display name

Root cause

The sidebar shell listened to UserDefaults.didChangeNotification and unconditionally called saveLayoutMode() from that listener. UserDefaults.set synchronously emitted the same notification, recursively re-entering the observer until the main thread exhausted its stack and crashed with EXC_BAD_ACCESS.

User impact

Lua v0.2.0 can crash while its first browser window appears. This patch removes the notification loop and makes future CI/release runs prove that the built app remains alive after launch.

Validation

• inspected five matching macOS crash reports; all show roughly 2,440 recursive notification frames
• verified the installed v0.2.0 app is correctly signed and notarized, isolating the failure to runtime startup code
• bash -n script/smoke_launch script/verify
• plutil -lint Phi.xcodeproj/project.pbxproj
• git diff --check
• local Xcode compilation unavailable because this machine currently has only Command Line Tools selected; CI is the authoritative build and runtime gate