- Add attunementLevel field to SkillDef type
- Organize skills into Core, Enchanter, Invoker, and Fabricator trees
- Core skills (mana, study, ascension) available to all players
- Enchanter skills require Enchanter attunement and scale with level
- Invoker skills for pact mastery and invocation (requires Invoker attunement)
- Fabricator skills for golemancy and fabrication (requires Fabricator attunement)
- Add attunement level requirements for advanced skills (Lv 3, 5, 7, 8)
- Update SkillsTab UI to show attunement requirements
- Update store to validate attunement requirements before studying
- Increase attunement mana conversion rates (0.2 -> 2 for Enchanter)
- Hide mana types with current < 1 in ManaDisplay and LabTab
- Only show owned equipment types when designing enchantments