Fix Minecraft 1.10.2 Eclipse development runtime

[SkyBlade1978]

Summary

Fixes the Minecraft 1.10.2 development environment after the ForgeGradle 7 migration. These changes do not alter Mineralogy or OreSpawn gameplay behavior and do not require a new public mod release.

Changes

• restore the Buildship project nature, builder, wrapper configuration, and shared Gradle-cache settings expected by ForgeGradle 7 Eclipse launches;
• retire obsolete ForgeGradle 2 launch files and normalize all generated Slime Launcher paths containing spaces;
• keep ordinary Eclipse client/server launches production-only while retaining the explicit test launches;
• mirror OreSpawn 4.0.6.110021's two access-transformer rules with mapped development names so new worlds do not fail with IllegalAccessError at WorldProvider.biomeProvider;
• audit the mapped development transformer against the exact SRG transformer packaged in the released OreSpawn jar, and prohibit the development transformer from entering Mineralogy artifacts;
• copy Gradle-processed resources into Eclipse's merged bin/main, ensuring expanded mcmod.info metadata and the bundled Mineralogy guides are available during IDE launches;
• document the development setup and add regression coverage for these contracts.

Validation

• focused VersionContractTest and DocumentationContractTest pass;
• genEclipseRuns and verifyEclipseProductionClasspath pass;
• verifyReleaseDependencies and verifyReleaseArtifacts pass against released OreSpawn 4.0.6.110021;
• production jar audit confirms no test/probe classes or development access transformer are packaged;
• disposable development dedicated server loaded exactly MCP/FML/Forge/OreSpawn/Mineralogy, exported all seven guide files, activated 32 rocks/3 ores/1 fluid deposit, loaded Overworld/Nether/End, generated spawn, reached Done, saved, and stopped cleanly;
• no crash report, IllegalAccessError, missing-guide failure, or test/probe classpath leakage occurred;
• git diff --check passes.

The remaining Forge 1.10 development-log noise is the established external baseline: Slime Launcher's Java 11 multi-release entry cannot be parsed by the legacy ASM scanner, Forge's obsolete update URL returns non-JSON, and development binaries are unsigned.

No tag, release, or publication is requested by this PR.