MCHeli Rework 1.0.0

First release. Everything from the alpha and beta versions, shipped as a code-only jar. The
features still open from phase 4 (night vision, equipment, drafting table, config and more) and
the vehicle workshop are planned for 1.1.0; see docs/ROADMAP.md.

Installing

This jar contains only the mod's code. The vehicles, models, textures and sounds are EMB4's
original MCHeli content, which you download yourself:

1. Install Forge 66.1.0 for Minecraft 26.3 and put mcheli-26.3-1.0.0.jar in the mods folder.

2. Download MC1.7.10_mcheli_1.0.3.zip from the
   MCHeli CurseForge page, Files tab.

3. Create a folder called mcheli next to mods and put the zip in it. Do not unzip it.

   .minecraft/
     mods/mcheli-26.3-1.0.0.jar
     mcheli/MC1.7.10_mcheli_1.0.3.zip
   

4. Start the game. The first start converts the zip, which takes a few seconds. If the zip is
   missing, the game still starts and the chat tells you where to put it.

Servers need the same two files. Only the zip goes in the mcheli folder, never in mods.

Changed

• The jar no longer contains EMB4's vehicles, models, textures, sounds or HUD scripts; it shrinks
  from 73 MB to under 0.5 MB. Players put the original MC1.7.10_mcheli_1.0.3.zip from the MCHeli
  CurseForge page into <game directory>/mcheli, and on start the mod converts it into
  mcheli/imported, which loads as a required resource pack and data pack ("MCHeli Content").
  The conversion runs again only when the zip changes; once done, the zip can be deleted.
  Dedicated servers need the zip as well.
• Crafting recipes are generated from the definitions during that conversion instead of shipping
  in the jar.
• Item names and achievement texts come from the imported zip. The lang files in the jar hold only
  the rework's own keys (HUD, key bindings, entities, creative tabs), and the bundled zh_cn
  file, which had none of those, is gone.
• tools/AssetMigrator.java is replaced by the importer inside the mod
  (content.LegacyImporter).
• The repository no longer holds any original files: the converted assets, the generated recipe
  copy and docs/legacy/original are gone. The unit tests import the zip from Mod/ into
  build/legacy-content instead and are skipped where it is missing, as on CI. The translated
  comments of the converted definitions went with them; the format guides in docs/content keep
  the translations that matter. -PupdateRecipes is no longer needed.

Added

• Without the zip the game still starts, with no vehicles, and the chat says where to put it on
  joining a world. A zip that fails to import reports the reason in the chat and the log.
• A guide to modeling vehicles in Blockbench or Blender (docs/content/modeling.md): axes,
  scale, part names, textures and export settings.
• A contributing guide (CONTRIBUTING.md) and issue and pull request templates.