Preserve legacy Mineralogy upgrades on Forge 1.20.1

[SkyBlade1978]

Summary

• preserves legacy Mineralogy 1.10.2/1.12.2 worlds and the last published legacy engine, Mineralogy 1.18.2 5.4.0
• writes atomic, idempotent upgrade reports without rewriting source configs or existing chunks
• preserves OreSpawn 4.0.4 world-profile precedence, Custom values, and providers
• adds strict runtime-log scanning and real flowing-water fresh/reload coverage

Validation

• 115 tests across 28 suites; zero failures or skips
• 2,304 surface columns per dimension and 38 stable flowing-water blocks
• 37 structured resources; 16 locales with 359 keys
• Java 17 offline clean build, Javadocs, Eclipse runs/metadata
• all release jars clean of fixtures, oracles, test worlds, and test resources

OreSpawn remains 4.0.6; API major 1 and schemas 4/6/5 are unchanged. A quick player/UI test remains before merge.