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/adapters/pf2e-bestiary-index-adapter.ts

@@ -0,0 +1,70 @@
+import type {
+	Pf2eBestiaryIndex,
+	Pf2eBestiaryIndexEntry,
+} from "@initiative/domain";
+
+import rawIndex from "../../../../data/bestiary/pf2e-index.json";
+
+interface CompactCreature {
+	readonly n: string;
+	readonly s: string;
+	readonly lv: number;
+	readonly ac: number;
+	readonly hp: number;
+	readonly pc: number;
+	readonly sz: string;
+	readonly tp: string;
+}
+
+interface CompactIndex {
+	readonly sources: Record<string, string>;
+	readonly creatures: readonly CompactCreature[];
+}
+
+function mapCreature(c: CompactCreature): Pf2eBestiaryIndexEntry {
+	return {
+		name: c.n,
+		source: c.s,
+		level: c.lv,
+		ac: c.ac,
+		hp: c.hp,
+		perception: c.pc,
+		size: c.sz,
+		type: c.tp,
+	};
+}
+
+let cachedIndex: Pf2eBestiaryIndex | undefined;
+
+export function loadPf2eBestiaryIndex(): Pf2eBestiaryIndex {
+	if (cachedIndex) return cachedIndex;
+
+	const compact = rawIndex as unknown as CompactIndex;
+	cachedIndex = {
+		sources: compact.sources,
+		creatures: compact.creatures.map(mapCreature),
+	};
+	return cachedIndex;
+}
+
+export function getAllPf2eSourceCodes(): string[] {
+	const index = loadPf2eBestiaryIndex();
+	return Object.keys(index.sources);
+}
+
+export function getDefaultPf2eFetchUrl(
+	sourceCode: string,
+	baseUrl?: string,
+): string {
+	const filename = `creatures-${sourceCode.toLowerCase()}.json`;
+	if (baseUrl !== undefined) {
+		const normalized = baseUrl.endsWith("/") ? baseUrl : `${baseUrl}/`;
+		return `${normalized}${filename}`;
+	}
+	return `https://raw.githubusercontent.com/Pf2eToolsOrg/Pf2eTools/dev/data/bestiary/${filename}`;
+}
+
+export function getPf2eSourceDisplayName(sourceCode: string): string {
+	const index = loadPf2eBestiaryIndex();
+	return index.sources[sourceCode] ?? sourceCode;
+}