Fix systray crash on macOS due to dual NSApplication run loops

[ehsaniara]

Summary

Fixes #11 — Egressor crashes with SIGTRAP: trace trap on macOS when the system tray runs alongside the Wails desktop UI.

• Replace systray.Run() with systray.Register() so the tray hooks into the existing Wails run loop instead of starting a competing NSApplication loop
• Remove the unnecessary go goroutine wrapper in App.Startup since Register is non-blocking
• Fix Policy tab layout to be fully resizable by removing the max-w-2xl constraint

Root Cause

systray.Run() starts its own NSApplication event loop, but Wails already owns the main thread. macOS requires all UI work on a single main thread — two competing run loops cause a fatal SIGTRAP
signal.