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/domain/src/index.ts

@@ -13,6 +13,7 @@ export {
 export {
 	CONDITION_DEFINITIONS,
 	type ConditionDefinition,
+	type ConditionEntry,
 	type ConditionId,
 	getConditionDescription,
 	getConditionsForEdition,
@@ -23,6 +24,7 @@ export {
 	createPlayerCharacter,
 } from "./create-player-character.js";
 export {
+	type AnyCreature,
 	type BestiaryIndex,
 	type BestiaryIndexEntry,
 	type BestiarySource,
@@ -31,6 +33,9 @@ export {
 	creatureId,
 	type DailySpells,
 	type LegendaryBlock,
+	type Pf2eBestiaryIndex,
+	type Pf2eBestiaryIndexEntry,
+	type Pf2eCreature,
 	proficiencyBonus,
 	type SpellcastingBlock,
 	type TraitBlock,
@@ -87,6 +92,7 @@ export type { ExportBundle } from "./export-bundle.js";
 export { deriveHpStatus, type HpStatus } from "./hp-status.js";
 export {
 	calculateInitiative,
+	calculatePf2eInitiative,
 	formatInitiativeModifier,
 	type InitiativeResult,
 } from "./initiative.js";
@@ -127,6 +133,8 @@ export {
 	toggleConcentration,
 } from "./toggle-concentration.js";
 export {
+	decrementCondition,
+	setConditionValue,
 	type ToggleConditionSuccess,
 	toggleCondition,
 } from "./toggle-condition.js";