Flexible race system with slot-based equipment and dragon race

- Expand race TOML schema: 7 stats, body shape (size/weight/custom slots),
  natural armor and attacks with damage types, resistances, traits/disadvantages,
  regen multipliers, vision types, XP rate, guild compatibility
- Replace equipped_weapon/equipped_armor with slot-based HashMap<String, Object>
- Each race defines available equipment slots; default humanoid slots as fallback
- Combat uses natural weapons/armor from race when no gear equipped
- DB migration from old weapon/armor columns to equipped_json
- Add Dragon race: huge body, custom slots (forelegs/wings/tail), fire breath,
  natural armor 8, fire immune, slow XP rate for balance
- Update all existing races with expanded fields (traits, resistances, vision, regen)
- Objects gain optional slot field; kind=weapon/armor still works as fallback
- Update chargen to display race traits, size, natural attacks, vision
- Update stats display to show equipment and natural bonuses separately
- Update TESTING.md and AGENTS.md with race/slot system documentation

Made-with: Cursor

world/town/objects/iron_shield.toml

@@ -2,6 +2,7 @@ name = "Iron Shield"
 description = "A dented but serviceable round shield bearing the blacksmith's mark."
 room = "town:forge"
 kind = "armor"
+slot = "off_hand"
 takeable = true
 
 [stats]

world/town/objects/rusty_sword.toml

@@ -2,6 +2,7 @@ name = "Rusty Sword"
 description = "A battered iron blade with a cracked leather grip. It's seen better days."
 room = "town:cellar"
 kind = "weapon"
+slot = "main_hand"
 takeable = true
 
 [stats]