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>

packages/application/src/index.ts

@@ -3,6 +3,7 @@ export { adjustHpUseCase } from "./adjust-hp-use-case.js";
 export { advanceTurnUseCase } from "./advance-turn-use-case.js";
 export { clearEncounterUseCase } from "./clear-encounter-use-case.js";
 export { createPlayerCharacterUseCase } from "./create-player-character-use-case.js";
+export { decrementConditionUseCase } from "./decrement-condition-use-case.js";
 export { deletePlayerCharacterUseCase } from "./delete-player-character-use-case.js";
 export { editCombatantUseCase } from "./edit-combatant-use-case.js";
 export { editPlayerCharacterUseCase } from "./edit-player-character-use-case.js";
@@ -21,6 +22,7 @@ export {
 } from "./roll-all-initiative-use-case.js";
 export { rollInitiativeUseCase } from "./roll-initiative-use-case.js";
 export { setAcUseCase } from "./set-ac-use-case.js";
+export { setConditionValueUseCase } from "./set-condition-value-use-case.js";
 export { setCrUseCase } from "./set-cr-use-case.js";
 export { setHpUseCase } from "./set-hp-use-case.js";
 export { setInitiativeUseCase } from "./set-initiative-use-case.js";