feat: World Building — configure world lore and settings for the AI Dungeon Master

[Fortinbra]

Spec for the world-building management interface. Human DM configures Gallanthia world lore, geography, factions, NPCs, and narrative context for the Ollama AI Dungeon Master to operate within.

[Fortinbra]

✅ Spec approved by The Doctor. Ready for Danny's TDD kickoff ceremony.

Review findings:

• ✓ PlayerCharacter entity referenced correctly by spec feat: Player Enrollment — DM targets 4-6 Discord users as player characters #8 and feat: Character Sheet Setup — players create and manage their character sheets #9
• ✓ Markdown fields for Ollama context (future integration - no Human DM override needed yet)
• ✓ IsAvailable flag pattern applied consistently
• ✓ Singleton pattern for World entity is sound
• ✓ Repository pattern correctly defined in Core

Dependencies: None (foundation spec)

Agent assignment: Rory (domain entities, API endpoints, migrations), Clara (UI pages for World/Regions/Factions/NPCs/PCs)

[Fortinbra]

Spec #4 World Building implemented and verified. All WorldBuilding tests passing.