Add configurable Wake-on-LAN target addresses

[Orkopaede]

Summary

This pull request adds support for configurable Wake-on-LAN target addresses.
Users can specify one or more IPv4 or IPv6 addresses in the application settings. When waking a host, Moonlight sends the Wake-on-LAN magic packet to each configured address on UDP port 9 before continuing with the existing Wake-on-LAN behavior.

Motivation

Standard Wake-on-LAN broadcasts do not work in some network configurations because broadcast packets are typically not routed across Layer 3 boundaries.
This is particularly relevant for setups such as:
• Hosts or virtual machines located in a different subnet
• VPN connections that only provide Layer 3 connectivity
• Routed networks where broadcast traffic is unavailable
• Networks using a Wake-on-LAN relay or proxy
• Custom network configurations where the normal broadcast destination is insufficient
Allowing users to configure additional target addresses makes it possible to forward the magic packet to a suitable relay, directed broadcast address, router, or other reachable endpoint.

Changes

• Add a new Wake-on-LAN proxy settings section
• Allow multiple IPv4 and IPv6 addresses separated by commas
• Validate addresses before saving them
• Reject hostnames, port numbers, and empty entries
• Normalize and deduplicate configured addresses
• Persist the address list in the application settings
• Send the magic packet to each configured address on UDP port 9
• Preserve the existing Wake-on-LAN behavior as a fallback
• Avoid sending duplicate packets to the same endpoint
• Add logging for successful and failed Wake-on-LAN packet transmissions

Example

A user can configure addresses such as:
192.168.1.255, 10.10.0.5, 2001:db8::10
When a host is woken, Moonlight first sends the magic packet to these configured targets and then performs the existing Wake-on-LAN attempts.
Compatibility
The setting is optional. When no custom addresses are configured, Wake-on-LAN continues to behave as before.
Both IPv4 and IPv6 literal addresses are supported. Hostnames and custom ports are intentionally not supported.

Testing

• Verified that valid IPv4 addresses are accepted
• Verified that valid IPv6 addresses are accepted
• Verified that multiple comma-separated addresses are parsed correctly
• Verified that whitespace is normalized
• Verified that duplicate addresses are removed
• Verified that invalid entries are rejected
• Verified that the setting is saved and restored
• Verified that packets are sent to configured targets on UDP port 9
• Verified that the existing Wake-on-LAN behavior still runs afterward

Development assistance

Parts of this change were developed with assistance from OpenAI Codex. The generated and suggested code was reviewed and adjusted before submission.