Multiple instances launched when opening lan-mouse GUI repeatedly

[tyvsmith]

Description

When launching lan-mouse (GUI mode, no args) multiple times, each invocation spawns a new daemon child process and opens a new GTK window. While the daemon detects the AlreadyRunning condition and the duplicate exits, the GUI layer does not check for an existing instance before spawning.

This results in:

• Unnecessary daemon child processes being spawned (they exit immediately, but it's wasteful)
• Duplicate GTK windows with separate IPC connections
• No window re-activation / raise behavior when the app is already open

Environment

• OS: Arch Linux
• Desktop: Hyprland (Wayland)
• lan-mouse version: 0.10.0

Expected Behavior

Launching lan-mouse when an instance is already running should:

1. Detect the existing daemon and reuse it (no new child process)
2. Raise/present the existing GTK window instead of creating a duplicate

Current Behavior

Each lan-mouse launch unconditionally:

1. Spawns a new lan-mouse daemon child process
2. Creates a new GTK window with a new IPC connection