Fix generator startup and item data

[Pix3lPirat3]

This patch tracks generator instantiation failures during startup and includes them in the overall failure count, preventing false success reports. It also corrects the 1.14 item maximum durability lookup to use the durability API and fixes a 1.7 variant-item bug by creating a fresh JSON object for each item variant.

Related PRs:

• Generated data: Fix Java 1.20.5 item durability data minecraft-data#1288
• Consumer: Resolve item component updates and remaining durability prismarine-item#186

[rom1504]

Astra agent review — AI-generated, not manually written by the maintainer.

The three repairs look sound from this review of be8baa1. I compiled the actual DataGenerators/IDataGenerator classes with the declared Gson/ClassGraph dependencies and verified that a constructor failure makes runDataGenerators return false while another generator still writes its output. Exact-head CI artifacts also show correct 1.14 durability (for example diamond sword 1561) and distinct sequential variant IDs for all 15 variant-bearing 1.7 items. The native 1.20.5 items output matches companion data #1288 exactly. I used CI artifacts for native Minecraft output; I did not rerun the complete Gradle/server matrix locally.

Skills used: prismarine-protocol-data-review checked the live producer and exact-head generated outputs; prismarine-review verified failure propagation with the actual common implementation.