Introduce adapter injection and migrate test suite

Replace direct adapter/persistence imports with context-based injection
(AdapterContext + useAdapters) so tests use in-memory implementations
instead of vi.mock. Migrate component tests from context mocking to
AllProviders with real hooks. Extract export/import logic from ActionBar
into useEncounterExportImport hook. Add bestiary-cache and
bestiary-index-adapter test suites. Raise adapter coverage thresholds
(68→80 lines, 56→62 branches).

77 test files, 891 tests, all passing.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/web/src/components/__tests__/source-fetch-prompt.test.tsx

@@ -4,6 +4,8 @@ import "@testing-library/jest-dom/vitest";
 import { cleanup, render, screen, waitFor } from "@testing-library/react";
 import userEvent from "@testing-library/user-event";
 import { afterEach, describe, expect, it, vi } from "vitest";
+import { createTestAdapters } from "../../__tests__/adapters/in-memory-adapters.js";
+import { AdapterProvider } from "../../contexts/adapter-context.js";
 import { SourceFetchPrompt } from "../source-fetch-prompt.js";
 
 const MONSTER_MANUAL_REGEX = /Monster Manual/;
@@ -13,6 +15,9 @@ afterEach(cleanup);
 const mockFetchAndCacheSource = vi.fn();
 const mockUploadAndCacheSource = vi.fn();
 
+// Uses context mock because fetchAndCacheSource/uploadAndCacheSource involve
+// real fetch() calls. The test controls success/failure to verify the
+// component's loading and error UI, not the fetching logic itself.
 vi.mock("../../contexts/bestiary-context.js", () => ({
 	useBestiaryContext: () => ({
 		fetchAndCacheSource: mockFetchAndCacheSource,
@@ -20,22 +25,23 @@ vi.mock("../../contexts/bestiary-context.js", () => ({
 	}),
 }));
 
-vi.mock("../../adapters/bestiary-index-adapter.js", () => ({
-	getDefaultFetchUrl: (code: string) =>
-		`https://example.com/bestiary/${code}.json`,
-	getSourceDisplayName: (code: string) =>
-		code === "MM" ? "Monster Manual" : code,
-	loadBestiaryIndex: () => ({ sources: {}, creatures: [] }),
-	getAllSourceCodes: () => [],
-}));
-
 function renderPrompt(sourceCode = "MM") {
 	const onSourceLoaded = vi.fn();
+	const adapters = createTestAdapters();
+	adapters.bestiaryIndex = {
+		...adapters.bestiaryIndex,
+		getDefaultFetchUrl: (code: string) =>
+			`https://example.com/bestiary/${code}.json`,
+		getSourceDisplayName: (code: string) =>
+			code === "MM" ? "Monster Manual" : code,
+	};
 	const result = render(
-		<SourceFetchPrompt
-			sourceCode={sourceCode}
-			onSourceLoaded={onSourceLoaded}
-		/>,
+		<AdapterProvider adapters={adapters}>
+			<SourceFetchPrompt
+				sourceCode={sourceCode}
+				onSourceLoaded={onSourceLoaded}
+			/>
+		</AdapterProvider>,
 	);
 	return { ...result, onSourceLoaded };
 }