Implement the 029-on-demand-bestiary feature that replaces the bundled XMM bestiary JSON with a compact search index (~350KB) and on-demand source loading, where users explicitly provide a URL or upload a JSON file to fetch full stat block data per source, which is then normalized and cached in IndexedDB (with in-memory fallback) so creature stat blocks load instantly on subsequent visits while keeping the app bundle small and never auto-fetching copyrighted content

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/adapters/bestiary-index-adapter.ts

@@ -0,0 +1,56 @@
+import type { BestiaryIndex, BestiaryIndexEntry } from "@initiative/domain";
+
+import rawIndex from "../../../../data/bestiary/index.json";
+
+interface CompactCreature {
+	readonly n: string;
+	readonly s: string;
+	readonly ac: number;
+	readonly hp: number;
+	readonly dx: number;
+	readonly cr: string;
+	readonly ip: number;
+	readonly sz: string;
+	readonly tp: string;
+}
+
+interface CompactIndex {
+	readonly sources: Record<string, string>;
+	readonly creatures: readonly CompactCreature[];
+}
+
+function mapCreature(c: CompactCreature): BestiaryIndexEntry {
+	return {
+		name: c.n,
+		source: c.s,
+		ac: c.ac,
+		hp: c.hp,
+		dex: c.dx,
+		cr: c.cr,
+		initiativeProficiency: c.ip,
+		size: c.sz,
+		type: c.tp,
+	};
+}
+
+let cachedIndex: BestiaryIndex | undefined;
+
+export function loadBestiaryIndex(): BestiaryIndex {
+	if (cachedIndex) return cachedIndex;
+
+	const compact = rawIndex as unknown as CompactIndex;
+	cachedIndex = {
+		sources: compact.sources,
+		creatures: compact.creatures.map(mapCreature),
+	};
+	return cachedIndex;
+}
+
+export function getDefaultFetchUrl(sourceCode: string): string {
+	return `https://raw.githubusercontent.com/5etools-mirror-3/5etools-src/main/data/bestiary/bestiary-${sourceCode.toLowerCase()}.json`;
+}
+
+export function getSourceDisplayName(sourceCode: string): string {
+	const index = loadBestiaryIndex();
+	return index.sources[sourceCode] ?? sourceCode;
+}