Add native NeoForge 26.2 support via FFAPI

[Magi1053]

Summary

Adds a native NeoForge module (Plan/neoforge) for Minecraft 26.2 that ships as its own PlanNeoForge-*.jar, same idea as Fabric. It reuses Plan’s existing Fabric listeners/mixins via Forgified Fabric API, with a normal NeoForge entrypoint (@Mod, neoforge.mods.toml, FML paths).

This is for NeoForge itself — not SpongeForge. SpongeForge only helps if you’re already on Sponge, and a lot of NeoForge mods don’t work there. C2ME is one example: if you need that (or similar) on NeoForge, Plan has to be a real NeoForge mod, not a Sponge plugin on SpongeForge. Native support also lets us publish on NeoForge Modrinth/Curse channels next to Fabric. (Tracking: #4810; separate from the old SpongeForge work in #4162.)

Caveats: FFAPI doesn’t have a 26.2 build yet, so this currently depends on 0.155.2+26.1.2+3.5.0 until Sinytra ships one. There’s a small Fabric-side tweak so shared types take PlanPlugin instead of only PlanFabric.

[AuroraLS3]

Hello.

This PR has been set as a draft for three weeks without activity,

From the way it references 2 other PRs and an issue you opened it appears AI generated - what's up?

[Magi1053]

The two other PRs was my failed attempt at using github stacks. This PR is a draft due to the stated reason being that FFAPI 26.2 had not yet released, and to be honest I have not been monitoring it.