Port Villager Workers 2.0.3 to NeoForge 1.21.1

[nekomario28]

Summary

• Ports Villager Workers 2.0.3 from Forge to NeoForge for Minecraft 1.21.1.
• Migrates registration, events, networking, screens/rendering, config, mixins, build metadata, and access transformers.
• Keeps Villager Recruits integration working and updates Courier route loading to the Recruits 1.15.2 client API.
• Retains existing gameplay behavior while adapting the project to NeoForge 21.1.219.

Validation

• Cross-mod GameTests: 4/4 passed.
• Recruits and Workers production JAR audits passed; duplicate ZIP entries: 0.
• NeoForge dedicated-server startup passed.
• Workers entities created successfully: 5/5.
• Courier implements Recruits IVillagerWorker: passed.
• Xvfb client startup and screen reach passed.
• CourierScreen class loading and Recruits route loading passed.

Environment

• Minecraft 1.21.1
• NeoForge 21.1.219
• Java 21
• Villager Recruits 1.15.2

Related Recruits port: talhanation/recruits#78

The contribution is intentionally presented as one commit to keep the loader migration reviewable. The final tree is identical to the validated Workers branch.