Release Grass Slabs 1.1 for Minecraft 1.12.2

[SkyBlade1978]

Brings the shared grass rules and optional Terrain Smoother ownership to Minecraft 1.12.2, retains standalone generation, improves mixed legacy-ID recovery and adds dirt/grass slab recombination recipes. Existing IDs, metadata, configuration defaults and schema-1 migration history are retained. Neither Building Pieces nor Terrain Smoother is required.

Updated player guides, public integration notes, release notes and CI artifact paths. No local notes, runtime files or agent material are included.

Verification:

• 46 unit tests; development and packaged server fresh/reload checks, each with 76 gameplay and eight world-generation checks.
• Direct 1.10 and adjacent 1.11 fixture upgrades and reloads.
• Standalone upgrade from the actual released 1.0.1.112021 jar, followed by reload: all four block IDs, seven states, container/dropped item counts, metadata, custom NBT and schema-1 counters retained. Source fixture unchanged.
• Standalone client models, recipe book, first-world rendering and reload.
• Javadocs, Eclipse isolation, workflow lint and archive audit; Java 8 bytecode, 18 languages and required licences.
• Two clean builds produce identical main, sources, Javadocs and checksums.

Main SHA-256: 90710E8FD66F0B19829A02F1FC6710A512263FF112531FB90777471DCD3CE5CF. This is the same main jar previously qualified in the combined modpack tests.

[SkyBlade1978]

The final exact packaged 1.12 client check also passed: models, recipe-book visibility, first-world rendering and reload. The source fixture remains unchanged, and the authoritative Sylvester source still matches its recorded hash. CI's main and sources jars match the local candidate; the Javadocs differ only in generated whitespace across Windows and Linux.