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/hooks/use-encounter-export-import.ts

@@ -0,0 +1,139 @@
+import type { ExportBundle } from "@initiative/domain";
+import { useCallback, useRef, useState } from "react";
+import { useEncounterContext } from "../contexts/encounter-context.js";
+import { usePlayerCharactersContext } from "../contexts/player-characters-context.js";
+import {
+	assembleExportBundle,
+	bundleToJson,
+	readImportFile,
+	triggerDownload,
+	validateImportBundle,
+} from "../persistence/export-import.js";
+
+export function useEncounterExportImport() {
+	const {
+		encounter,
+		undoRedoState,
+		isEmpty: encounterIsEmpty,
+		setEncounter,
+		setUndoRedoState,
+	} = useEncounterContext();
+	const { characters: playerCharacters, replacePlayerCharacters } =
+		usePlayerCharactersContext();
+
+	const [importError, setImportError] = useState<string | null>(null);
+	const [showExportMethod, setShowExportMethod] = useState(false);
+	const [showImportMethod, setShowImportMethod] = useState(false);
+	const [showImportConfirm, setShowImportConfirm] = useState(false);
+	const pendingBundleRef = useRef<ExportBundle | null>(null);
+	const importFileRef = useRef<HTMLInputElement>(null);
+
+	const handleExportDownload = useCallback(
+		(includeHistory: boolean, filename: string) => {
+			const bundle = assembleExportBundle(
+				encounter,
+				undoRedoState,
+				playerCharacters,
+				includeHistory,
+			);
+			triggerDownload(bundle, filename);
+		},
+		[encounter, undoRedoState, playerCharacters],
+	);
+
+	const handleExportClipboard = useCallback(
+		(includeHistory: boolean) => {
+			const bundle = assembleExportBundle(
+				encounter,
+				undoRedoState,
+				playerCharacters,
+				includeHistory,
+			);
+			void navigator.clipboard.writeText(bundleToJson(bundle));
+		},
+		[encounter, undoRedoState, playerCharacters],
+	);
+
+	const applyImport = useCallback(
+		(bundle: ExportBundle) => {
+			setEncounter(bundle.encounter);
+			setUndoRedoState({
+				undoStack: bundle.undoStack,
+				redoStack: bundle.redoStack,
+			});
+			replacePlayerCharacters([...bundle.playerCharacters]);
+		},
+		[setEncounter, setUndoRedoState, replacePlayerCharacters],
+	);
+
+	const handleValidatedBundle = useCallback(
+		(result: ExportBundle | string) => {
+			if (typeof result === "string") {
+				setImportError(result);
+				return;
+			}
+			if (encounterIsEmpty) {
+				applyImport(result);
+			} else {
+				pendingBundleRef.current = result;
+				setShowImportConfirm(true);
+			}
+		},
+		[encounterIsEmpty, applyImport],
+	);
+
+	const handleImportFile = useCallback(
+		async (e: React.ChangeEvent<HTMLInputElement>) => {
+			const file = e.target.files?.[0];
+			if (!file) return;
+			if (importFileRef.current) importFileRef.current.value = "";
+
+			setImportError(null);
+			handleValidatedBundle(await readImportFile(file));
+		},
+		[handleValidatedBundle],
+	);
+
+	const handleImportClipboard = useCallback(
+		(text: string) => {
+			setImportError(null);
+			try {
+				const parsed: unknown = JSON.parse(text);
+				handleValidatedBundle(validateImportBundle(parsed));
+			} catch {
+				setImportError("Invalid file format");
+			}
+		},
+		[handleValidatedBundle],
+	);
+
+	const handleImportConfirm = useCallback(() => {
+		if (pendingBundleRef.current) {
+			applyImport(pendingBundleRef.current);
+			pendingBundleRef.current = null;
+		}
+		setShowImportConfirm(false);
+	}, [applyImport]);
+
+	const handleImportCancel = useCallback(() => {
+		pendingBundleRef.current = null;
+		setShowImportConfirm(false);
+	}, []);
+
+	return {
+		importError,
+		showExportMethod,
+		showImportMethod,
+		showImportConfirm,
+		importFileRef,
+		setImportError,
+		setShowExportMethod,
+		setShowImportMethod,
+		handleExportDownload,
+		handleExportClipboard,
+		handleImportFile,
+		handleImportClipboard,
+		handleImportConfirm,
+		handleImportCancel,
+	} as const;
+}