Gem system & fusion lab

Implemented the gem shard system: 7 gem types across 5 tiers that slot into your build for stat bonuses. Primal shards boost raw power. Vital shards add survivability. Arcane shards amplify magic damage.

Built the fusion lab where you combine lower-tier gems into higher ones. The RNG is tuned so that fusion feels like gambling with purpose. You're always progressing, but a lucky roll changes everything.