Release Base Metals 2.6.0 for Minecraft 1.12.2

[SkyBlade1978]

Base Metals 2.6.0 for Minecraft 1.12.2

This brings the tested 1.12 release work back to MMD: gameplay fixes, restored
achievements and recipe-book unlocks, optional Low Fantasy content, OreSpawn
4.1 world generation, and the modern build and release pipeline.

High Fantasy remains the default, including for unchanged older configuration
files. Blocks and items keep their saved registry names. The content mode is
an installation or server setting, not a per-world setting. Both configuration
entry points use the same Forge screen, with translations in all 18 locales.

Bug fixes

• Fixes #473:
  removed the blanket furnace fuel values from metal nuggets and powders.
  Coal and charcoal forms retain their intended fuel values.
• Fixes #474:
  doors and trapdoors have distinct recipes. Vanilla Bits forms, including
  Diamond and Gold doors, are registered and available as intended.
• Fixes #467:
  • TAIGA keeps its Adamant alias; Base Metals Adamantine no longer takes it.
  • Fishing rods use their material's durability. Wear still follows vanilla
    fishing rules, so a normal empty cast into water does not damage the rod.
  • Steel rails produce 16, matching vanilla, with recipe-book discovery.
  • Crossbows spawn bolts on the server, so hits deal damage.
  • Launcher and ammunition materials both contribute to shot damage before
    Power bonuses. Vanilla bow-and-arrow base damage remains unchanged.
  • Bolts use the valid vanilla arrow projectile texture.
  • Base Metals arrows retain their item identity when picked up.
  • The required OreSpawn 4.1 runtime is tested in fresh and reloaded worlds.
    Crossbows retain their original draw-and-release design; charge storage
    is not added by this PR.
• Fixes #470
  and #450:
  armor counting uses equipped item identity instead of damage-sensitive stack
  comparisons. Aquarium's submerged full-suit effects and damaged Starsteel
  armor's movement bonuses work, alongside the other material armor effects.
• Fixes #455:
  Tinkers casting and alloys skip disabled or absent materials and fluids,
  including Prismarine, instead of registering invalid recipes.
• Fixes #449:
  Base Metals hoes return the tool-material enum name that Ancient Warfare 2
  expects. Packaged tests cover AW2 both present and absent.
• Fixes #448
  and fixes #428:
  OreSpawn 4.1 is the required, sole generator. The API provider keeps all eleven
  historical rule IDs and distributions, preserves migrated user overrides,
  and supports disabling its rules for CoFH World without a fallback generator.
• Fixes #468:
  ForgeGradle 7 replaces the retired build setup. Pinned GitHub Actions run unit
  tests, packaged runtime tests, dependency and artifact audits, Eclipse
  isolation, cold-cache bootstrap, and reproducibility checks.

Other changes

• Recipe-book unlocks accept matching Ore Dictionary ingredients and group
  recipes by their actual output, not entire weapon or tool families.
• Plate repair requires one damaged matching item and one plate, accepts any
  crafting slots, preserves NBT, rejects extra ingredients, and stays out of
  the recipe book. Existing recipe IDs and configuration conditions remain.
• Restored all 18 historical gameplay achievements with saved progress.
• Low Fantasy filters crafting, smelting, crushing, trades, chest loot,
  shield upgrades, and supported integrations while keeping items registered
  for existing saves and creative access. Client/server mode checks compare
  effective values, so missing and explicit High Fantasy settings agree.
• The config screen opens through both Forge's Mods list and OreSpawn's cog.
• Build scripts are split by purpose. Source layout and comments have been
  cleaned up, with syntax comparisons checking the style-only changes.
• README, changelog, and guides now describe this release rather than the
  old build services or the discarded development experiments.

Verification

Local checks cover unit tests, JSON/provider validation, a clean release build,
release-JAR audit, checksums, Eclipse generation and isolation, and packaged
fresh/reload servers. Runtime profiles cover OreSpawn migration and dependency
rejection, CoFH World, Ancient Warfare 2, Tinkers with and without TAIGA,
Construct's Armory, disabled Prismarine, plate repair, both content modes,
and gameplay achievements. A disposable client probe checks both config-screen
entry points. The release archives are built twice and compared byte for byte.

The release requires MMDLib and OreSpawn 4.1.0.112021 or newer in the 4.x line.
Qualification uses the exact published OreSpawn 4.1.0.112021 artifact.

MMDLib itself is unchanged. Its separate reports, including the
Brittle modifier crash,
are not claimed fixed here. The 1.10 and 1.13 branches are not changed.