Port OreSpawn 4.0.16 to Forge 1.16.5

[SkyBlade1978]

Summary

Ports the accepted OreSpawn 4.0.10–4.0.16 campaign to Forge 1.16.5 and
finishes at 4.0.16.116051.

This retains the existing 4.0.8 field-persistence work and the 4.0.9 natural
terrain-host repair, then adds:

• actual-world-Y rock eligibility while preserving shifted Stable Layers
  formation identity;
• dynamic biome matching through the active Forge 1.16 registry and
  BiomeDictionary, with stable RegistryKey<Biome> ore filters;
• public sampler first-free/highest-occupied height alignment;
• Ore-dimension exact and dictionary biome include/exclude builder/getter
  contracts using the existing provider JSON fields;
• canonical namespaced and legacy unnamespaced geome editor support;
• exposed one-layer Snow handling at top + 1, while preserving buried or
  authored Snow/Ice and unsafe source states;
• direct quart-biome attribution shared by generated geology and public
  sampling, using BiomeContainer.getNoiseBiome and
  BiomeManager.getNoiseBiomeAtQuart with correct negative-coordinate floor
  semantics.

Forge 1.16 has no server-side GameTest harness class, so the 4.0.16
GameTest-ownership repair is recorded as target-inapplicable. The existing
ordinary dedicated-server benchmark auto-stop remains in place and is covered
by a real packaged benchmark.

Target-specific build and compatibility work

• Preserves Minecraft 1.16.5, Forge 36.2.34, ForgeGradle 7.0.34, Gradle 9.6.1,
  Java 8 bytecode, pack format 6, API 1 and schemas 4/6/5.
• Preserves reobfuscation and all six packaged access-transformer rules.
• Keeps Forge 36's required duplicated merged bin/main MOD_CLASSES
  entries and production-only Eclipse launches.
• Adds a cache-disabled Forge 36 bootstrap with Temurin 8.0.502+7 compilation
  and Java 17 Gradle execution. Empty-cache qualification confirmed that Forge
  36 needs no Mavenizer compatibility patch.
• Updates version/report/Maven/workflow identities and all release
  documentation to 4.0.16.116051.

No API major, schema, registry ID, provider-field meaning, profile filename,
migration behavior or existing chunk is changed. Compatibility remains
[4.0.6,5.0.0).

Validation

• Manually accepted exact candidate:
  a6bc7ee3f621b71b46025ee91b976d4d51e9b07a.
• 127 tests across 33 suites; zero failures, errors or skips.
• 28 JSON/mcmeta files parse; all 16 locales contain the same 357 keys.
• All 21 documentation exports are byte-identical; Javadocs are warning-free.
• Full offline release/audit lifecycle and ForgeGradle Eclipse isolation pass
  in both the primary checkout and a cold exact-commit worktree.
• Empty Gradle-home online bootstrap and same-cache offline replay pass.
• Exact reobfuscated Forge 36 packaged client and fresh/reload server pass,
  including world creation, rendering, editors, save/reopen and clean stop.
• Surface, natural-host, height, dynamic-biome, exact/family ore, Snow/Ice,
  flowing-fluid and sampler-attribution regressions pass fresh and reload.
• Strict runtime/crash scans found no rejected errors or fixture leakage.
• Three matched 81-chunk medians: vanilla 17.575, Cyano 19.051 and Sky 16.599
  ms/chunk. Sky is +7.849% direct and -5.339% control-normalized versus the
  accepted 4.0.9 evidence, below the 10% investigation threshold.
• Main jar SHA-256:
  B3D61A15F44845A5AB3A3869338BBA7E867F24F32275A03FAE28BC3B4029DE22.

This PR updates MMD source only. It does not create a tag, publish artifacts,
update issues or directly modify the MMD target branch.

[SkyBlade1978]

CI follow-up is fixed in e5e75b032158bafe1695ff2b4c618a650f0fb9a4.

The failure was confined to hosted build setup: ForgeGradle 7 requested a Java 25 toolchain for Minecraft Mavenizer during configuration, while the 1.16 workflows installed and exposed only Java 8 and Java 17. The repair installs pinned Temurin 25 first, retains Temurin 8 for compilation/fixtures, installs Temurin 17 last so it remains JAVA_HOME, and passes all three paths with auto-detection/provisioning disabled. The workflow regression now checks every CI job independently for the complete JDK order and path list.

Verification:

• local full offline lifecycle: 127 tests across 33 suites, fresh/reload surface gate, Javadocs, release-artifact audit and checksums passed;
• disposable exact-commit empty-cache bootstrap rebuilt Forge 36 successfully, followed by a successful same-cache offline replay;
• main, sources and Javadoc SHA-256 values remain byte-identical to the manually accepted candidate;
• hosted Cold Forge bootstrap, Build, test, and audit, wrapper validation and CodeQL are all green.

This is build/CI documentation only: OreSpawn runtime code and version 4.0.16.116051 are unchanged.