fix: tray show opens main window on first click

[mxyhi]

Problem

When the main window has been hidden/destroyed, clicking tray "显示主窗口" the first time may only recreate the window object but not actually present it, so users have to click twice.

Root cause

The create path only built the window and synced menu state. Since tauri.conf.json sets visible: false, a newly created window can stay hidden unless we explicitly show/focus it.

Fix

• In the create path of show_or_create_main_window, capture the newly built window
• Explicitly call unminimize(), show(), and set_focus()
• Keep menu sync after successful creation

Verification

• cargo check -q -p token_proxy
• cargo test -q -p token_proxy tray::tests