fix: respect Unbreaking (Прочность) when consuming shears/axe durability

[iSlavok]

Problem

The Прочность enchantment (vanilla Unbreaking) had no effect when the mod/plugin
consumes tool durability: the shears (invisibility toggle) and the axe (wax removal) lost a
durability point on every use. Root cause: durability was decremented unconditionally,
bypassing vanilla Unbreaking.

Vanilla mechanic for a non-armor tool: a durability point is applied only with probability
1/(level+1) — i.e. skipped when random.nextInt(level+1) != 0. Level 0 → always applied,
so existing behaviour is preserved for un-enchanted tools.

This fix covers both platforms in the repo.

Plugin (Bukkit/Paper — plugin/)

• Unified the byte-for-byte-identical damageShears/damageAxe into one damageTool.
• Resolve the Unbreaking level version-stably via Enchantment.getByKey(minecraft("unbreaking"))
  • getEnchantmentLevel (0 if absent).
• Apply a point only when the roll says so; RNG is an injectable constructor default param
  (random: java.util.Random = java.util.Random()) so existing FrameListener(plugin) call
  sites still compile.
• Extracted the pure decision to internal fun consumesDurability(level, random) for unit tests.
• New unit tests: level 0 always consumes (loop), a negative level always consumes, and
  Unbreaking III consumes ~1/4 of the time (tolerance band, seeded RNG).

Fabric mod (src/ — Stonecutter multi-version)

• Gated both durability sites (shears in injectDamage, axe in injectWax) on the
  1/(level+1) roll using the world RNG — in both the yarn and mojmap (>=1.22) branches.
• Added a cross-version unbreakingLevel helper, Stonecutter-branched because the enchantment
  API churns per version:
  • <1.21 (yarn): plain Enchantment object → EnchantmentHelper.getLevel(Enchantment, stack).
  • 1.21–1.21.1 (yarn): registry entry via manager.getOptionalWrapper(...).getOrThrow(...).
  • 1.21.2+ (yarn): registry entry via manager.getOrThrow(...).getOrThrow(...).
  • 1.22+ (mojmap): Holder via registryAccess().lookupOrThrow(...).getOrThrow(...) +
    getItemEnchantmentLevel.
• The lookup is wrapped in the mixin's existing try/catch logging idiom; on any failure it
  returns level 0 (safe fallback = previous always-consume behaviour), so a bad lookup can
  never crash the interaction.
• The gametest now asserts an Unbreaking-3 stack reads back level 3 through the same
  cross-version lookup (deterministic) — this catches a silent registry-resolution failure
  that compilation alone cannot.

Test evidence (run locally, offline)

• Plugin: ./gradlew -p plugin test → green, 27 tests (incl. the 3 new probability/level tests).
• Fabric: ./gradlew build → BUILD SUCCESSFUL, all 9 anchors' :build tasks ran
  (yarn 1.18.2/1.19.4/1.20.4/1.20.6/1.21.1/1.21.8/1.21.10 and mojmap 26.1.2/26.2 on JDK 25).
• Gametest: runGameTest on all 4 gametest-enabled nodes (1.20.6, 1.21.1, 1.21.8, 1.21.10) →
  "All required tests passed" on each, exercising the <1.21, 1.21–1.21.1, and 1.21.2+
  enchantment-lookup branches at runtime.

The mojmap >=1.22 branch was compiled locally (JDK 25 toolchain available in the sandbox);
its gametest is not enabled for 26.x (mod matrix), matching CI.