Bring Base Metals to Minecraft 1.16.5

[SkyBlade1978]

This brings the tested 1.15 release to Minecraft 1.16.5 and Forge 36.2.34 as Base Metals 3.1.0.116051.

The materials, saved item names, High/Low Fantasy modes and eleven OreSpawn rules stay the same. OreSpawn 4.1.0.116051 is pinned to its published CurseForge file and checksum. There is no MMDLib dependency or second ore generator.

The main changes are:

• Update the configuration screens, fluids, projectiles, wall connections and old-world upgrade support for 1.16.
• Increase the gap between Kiri's ore overlays and their vanilla backgrounds to reduce flickering at a distance.
• Use Forge's fluid-bucket models and clearer translated names for all 36 filled buckets.
• Let Crack Hammers crush Nether gold ore into two gold powders and Ancient Debris into two Netherite scraps.
• Keep ForgeGradle 7, Java 8 game compatibility, isolated test launches and reproducible release jars.

I've updated the README, changelog and guides for this version, and checked that agent notes, generated worlds, logs and local test reports are not included.

Local checks passed: 67 unit tests, generated resources, dependency and jar audits, Eclipse isolation, and packaged client/server fresh-world and reload tests. The port's disposable upgrade checks cover Cyano and MMD 1.10, MMD 1.12, 1.13, 1.14 and 1.15 worlds. Clean builds produced identical main, sources and Javadoc jars. The overlay and bucket changes have also been tested in-game.

Please merge into master-1.16.5 once the checks pass. The release will use the existing default-branch dispatcher after the merged commit passes CI.