Add Pathfinder 2e game system mode

Implements PF2e as an alternative game system alongside D&D 5e/5.5e.
Settings modal "Game System" selector switches conditions, bestiary,
stat block layout, and initiative calculation between systems.

- Valued conditions with increment/decrement UX (Clumsy 2, Frightened 3)
- 2,502 PF2e creatures from bundled search index (77 sources)
- PF2e stat block: level, traits, Perception, Fort/Ref/Will, ability mods
- Perception-based initiative rolling
- System-scoped source cache (D&D and PF2e sources don't collide)
- Backwards-compatible condition rehydration (ConditionId[] → ConditionEntry[])
- Difficulty indicator hidden in PF2e mode (excluded from MVP)

Closes dostulata/initiative#19

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/contexts/adapter-context.tsx

@@ -3,6 +3,7 @@ import type {
 	BestiaryCachePort,
 	BestiaryIndexPort,
 	EncounterPersistence,
+	Pf2eBestiaryIndexPort,
 	PlayerCharacterPersistence,
 	UndoRedoPersistence,
 } from "../adapters/ports.js";
@@ -13,6 +14,7 @@ export interface Adapters {
 	playerCharacterPersistence: PlayerCharacterPersistence;
 	bestiaryCache: BestiaryCachePort;
 	bestiaryIndex: BestiaryIndexPort;
+	pf2eBestiaryIndex: Pf2eBestiaryIndexPort;
 }
 
 const AdapterContext = createContext<Adapters | null>(null);