Separate NeoGradle clean from release builds

[SkyBlade1978]

Summary

• run NeoForge release cleaning in a separate Gradle invocation before model-consuming build tasks
• retain the established single-invocation Forge release lifecycle unchanged
• cap NeoForge release builds at two Gradle workers, matching the qualified target CI contract

Failure fixed

Release run 33993162510 failed in neoFormSetup because clean removed NeoGradle's configuration-time build/tmp/.cache expansion before it could read patches.lzma. No release tag or publication was created.

Validation

• exact NeoForge 26.2 two-invocation release lifecycle passed on Java 25 / Gradle 9.2.1
• 141 tests across 33 suites passed with no failures, errors, or skips
• fresh and reload surface integration passed
• Javadocs, exact three-jar audit, and SHA-256 generation passed
• main candidate remained byte-identical: 16DFD59B5083BB1F7FE399091AC9778F9D10F397FE214865C937F00D1C20625A
• actionlint 1.7.12 passed for the edited dispatcher
• fork CodeQL and Gradle wrapper validation passed; fork legacy CI is still running

After merge, rerun the normal release form for 4.0.16.2602002.