Support Minecraft 26.1.2 in prismarine-viewer

[mneuhaus]

Summary

Adds Minecraft 26.1.2 support to prismarine-viewer and fixes the browser worker bundle so it keeps the bedrock version indexes required by minecraft-data initialization.

Without the worker fix, the browser viewer could start with the right 26.1.2 data but fail during bundled data initialization.

Testing

Validated locally with:

• npm run lint
• npm run prepare / webpack build
• browser screenshot smoke test using version 26.1.2

Evidence summary: https://gist.github.com/mneuhaus/decaae9cd8767a651272d31cdf97ac60

Related PRs

Part of the Minecraft 26.1.2 update chain:

1. Support nested item model references minecraft-jar-extractor#67 - nested item model extraction support
2. Add Minecraft 26.1.2 assets minecraft-assets#48 - generated 26.1.2 assets
3. Add Minecraft 26.1.2 assets wrapper node-minecraft-assets#52 - assets wrapper update
4. Add Minecraft 26.1.2 data minecraft-data#1186 - 26.1.2 protocol/data plus generated block/item data
5. Update wrapper data for Minecraft 26.1.2 node-minecraft-data#455 - wrapper update for the generated data
6. Add Minecraft 26.1.2 protocol support node-minecraft-protocol#1487 - 26.1.2 protocol support/tests
7. Support Minecraft 26.1.2 chunk fluid counts prismarine-chunk#326 - 26.1.2 chunk fluid count support
8. Add 26.1 physics feature flags prismarine-physics#134 - 26.1 physics feature flags
9. Update Mineflayer for Minecraft 26.1.2 mineflayer#3902 - full Mineflayer external-suite compatibility
10. Support Minecraft 26.1.2 in prismarine-viewer #480 - 26.1.2 viewer support

The dependent PRs are opened as drafts so they can be reviewed/merged in order.

Implementation note

Prepared with assistance from GPT-5.5 and validated locally with the checks listed above.