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/__tests__/adapters/in-memory-adapters.ts

@@ -1,5 +1,5 @@
 import {
-	type Creature,
+	type AnyCreature,
 	type CreatureId,
 	EMPTY_UNDO_REDO_STATE,
 	type Encounter,
@@ -12,10 +12,10 @@ export function createTestAdapters(options?: {
 	encounter?: Encounter | null;
 	undoRedoState?: UndoRedoState;
 	playerCharacters?: PlayerCharacter[];
-	creatures?: Map<CreatureId, Creature>;
+	creatures?: Map<CreatureId, AnyCreature>;
 	sources?: Map<
 		string,
-		{ displayName: string; creatures: Creature[]; cachedAt: number }
+		{ displayName: string; creatures: AnyCreature[]; cachedAt: number }
 	>;
 }): Adapters {
 	let storedEncounter = options?.encounter ?? null;
@@ -25,7 +25,7 @@ export function createTestAdapters(options?: {
 		options?.sources ??
 		new Map<
 			string,
-			{ displayName: string; creatures: Creature[]; cachedAt: number }
+			{ displayName: string; creatures: AnyCreature[]; cachedAt: number }
 		>();
 
 	// Pre-populate sourceStore from creatures map if provided
@@ -33,7 +33,7 @@ export function createTestAdapters(options?: {
 		// No-op: creatures are accessed directly from the map
 	}
 
-	const creatureMap = options?.creatures ?? new Map<CreatureId, Creature>();
+	const creatureMap = options?.creatures ?? new Map<CreatureId, AnyCreature>();
 
 	return {
 		encounterPersistence: {
@@ -55,8 +55,9 @@ export function createTestAdapters(options?: {
 			},
 		},
 		bestiaryCache: {
-			cacheSource(sourceCode, displayName, creatures) {
-				sourceStore.set(sourceCode, {
+			cacheSource(system, sourceCode, displayName, creatures) {
+				const key = `${system}:${sourceCode}`;
+				sourceStore.set(key, {
 					displayName,
 					creatures,
 					cachedAt: Date.now(),
@@ -66,21 +67,25 @@ export function createTestAdapters(options?: {
 				}
 				return Promise.resolve();
 			},
-			isSourceCached(sourceCode) {
-				return Promise.resolve(sourceStore.has(sourceCode));
+			isSourceCached(system, sourceCode) {
+				return Promise.resolve(sourceStore.has(`${system}:${sourceCode}`));
 			},
-			getCachedSources() {
+			getCachedSources(system) {
 				return Promise.resolve(
-					[...sourceStore.entries()].map(([sourceCode, info]) => ({
-						sourceCode,
-						displayName: info.displayName,
-						creatureCount: info.creatures.length,
-						cachedAt: info.cachedAt,
-					})),
+					[...sourceStore.entries()]
+						.filter(([key]) => !system || key.startsWith(`${system}:`))
+						.map(([key, info]) => ({
+							sourceCode: key.includes(":")
+								? key.slice(key.indexOf(":") + 1)
+								: key,
+							displayName: info.displayName,
+							creatureCount: info.creatures.length,
+							cachedAt: info.cachedAt,
+						})),
 				);
 			},
-			clearSource(sourceCode) {
-				sourceStore.delete(sourceCode);
+			clearSource(system, sourceCode) {
+				sourceStore.delete(`${system}:${sourceCode}`);
 				return Promise.resolve();
 			},
 			clearAll() {
@@ -104,5 +109,12 @@ export function createTestAdapters(options?: {
 			},
 			getSourceDisplayName: (sourceCode) => sourceCode,
 		},
+		pf2eBestiaryIndex: {
+			loadIndex: () => ({ sources: {}, creatures: [] }),
+			getAllSourceCodes: () => [],
+			getDefaultFetchUrl: (sourceCode) =>
+				`https://example.com/creatures-${sourceCode.toLowerCase()}.json`,
+			getSourceDisplayName: (sourceCode) => sourceCode,
+		},
 	};
 }