Unity package for OpenUPM (com.m4bwav.random-name-generator)

[m4bwav]

Adds a Unity package so the library can be listed on OpenUPM.

• Packages/com.m4bwav.random-name-generator carries the netstandard2.0 DLL and XML docs from the nuget.org 2.3.0 package byte for byte. Unity can't compile the source, because the name lists are embedded resources. tools/UnityPackage/sync.py <version> copies a release's files from nuget.org, and --check proves they match. The NuGet package itself is unchanged.
• Unity-written .meta files, LICENSE.md, a package README, and an editor check that logs an error when a Web build has Use Embedded Resources off. Without that setting, Web builds leave the name lists out and every generator throws.
• OpenUPM builds from upm/<version> tags (gitTagPrefix: upm/); release.yml only reacts to v*.
• README: Unity install section, and the thread-safety sentence reworded (the netstandard2.0 build, Unity included, is one generator per thread). AGENTS.md: the release ritual gains the Unity step.

Checked: seeded names in Unity 6000.6.4f1 (Mono, Editor) and in a 6000.5.8f1 WebGL/IL2CPP player with stripping High are identical to dotnet run against nuget.org 2.3.0. Details are in ai-docs/notes/2026-10-11-openupm-unity-package.md.