QuestManager, InventoryManager, GuildManager, CombatManager, and
MagicManager all had load() methods that were never called. This
meant quests were never seeded, items never appeared in rooms, and
all game data started empty on every server restart.
Fixes#1351
World state: added explicit exits dict to all 5 rooms
Bridge: reads exits from world_state.json first, falls back to description parsing
Before: inner rooms (Tower, Garden, Forge, Bridge) had no exits
After: all rooms bidirectional — Threshold connects to all 4, each connects back
