Update Fabric target to 26.2

[alezhshede]

Summary

• Update the Fabric build to Minecraft 26.2, Fabric Loader 0.19.3, Fabric API 0.154.2+26.2, and Chunky Fabric 1.5.3.
• Port the Fabric integration code to the current networking, naming, teleport, particle, and rendering APIs.
• Move client-only Fabric code into the client source set and update Gradle/Shadow/Java tooling needed for the 26.2 build.

Scope notes

• No new gameplay features are intended here.
• Non-Fabric Gradle resource expansion changes are limited to Gradle 9 Kotlin DSL compatibility so the multi-project build can configure while building Fabric.

Checks

• ./gradlew.bat :chunkyborder-fabric:build
• Local Fabric 26.2 server smoke test with Chunky 1.5.3, Fabric API 0.154.2+26.2, and the built ChunkyBorder jar.

[pop4959]

I approved the action to run, so if anyone wants to test they can do so by downloading from the Github Actions tab.

Thanks for taking a look at this! I'll do a manual review later when I have time.

[alezhshede]

NeoForge runtime test note:

I tried smoke-testing the NeoForge 26.2 build in a local NeoForge 26.2.0.9-beta server with:

• ChunkyBorder NeoForge from this PR
• Chunky NeoForge 1.5.3
• Minecraft 26.2

The server does not currently get far enough to test ChunkyBorder behavior because Chunky NeoForge 1.5.3 declares Minecraft compatibility as [26.1,26.2), so NeoForge rejects it on Minecraft 26.2:

Mod chunky requires minecraft 26.1 or above, and below 26.2
Currently, minecraft is 26.2

[alezhshede]

Follow-up NeoForge smoke test:

I did one local-only test to check whether the ChunkyBorder NeoForge changes work once Chunky itself is allowed to load on Minecraft 26.2.

The current official/distributable Chunky NeoForge 1.5.3 jar still declares Minecraft compatibility as [26.1,26.2), so NeoForge rejects it on 26.2 before ChunkyBorder can be tested normally.

For the smoke test only, I patched the local Chunky NeoForge jar metadata to allow 26.2 and did not change ChunkyBorder. With that bypass:

• NeoForge 26.2.0.9-beta server started.
• Chunky 1.5.3 loaded.
• ChunkyBorder from this PR loaded.
• /chunky border add created a border.
• The border rendered/visualized in-game and enforcement appeared to work.

So from this local test, the ChunkyBorder NeoForge side appears functional, but the official blocker is that Chunky NeoForge itself needs a 26.2-compatible release/metadata update before this can be tested cleanly without a local bypass.