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/__tests__/stat-block-collapse-pin.test.tsx

@@ -5,7 +5,9 @@ import type { Creature, CreatureId } from "@initiative/domain";
 import { cleanup, fireEvent, render, screen } from "@testing-library/react";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
-// Mock the context modules
+// Uses context mocks because StatBlockPanel requires fine-grained control over
+// panel state (collapsed/expanded, pinned/unpinned, wide/narrow desktop) that
+// would need extensive setup to drive through real providers.
 vi.mock("../contexts/side-panel-context.js", () => ({
 	useSidePanelContext: vi.fn(),
 }));
@@ -14,14 +16,6 @@ vi.mock("../contexts/bestiary-context.js", () => ({
 	useBestiaryContext: vi.fn(),
 }));
 
-// Mock adapters to avoid IndexedDB
-vi.mock("../adapters/bestiary-index-adapter.js", () => ({
-	loadBestiaryIndex: () => ({ sources: {}, creatures: [] }),
-	getAllSourceCodes: () => [],
-	getDefaultFetchUrl: () => "",
-	getSourceDisplayName: (code: string) => code,
-}));
-
 import { StatBlockPanel } from "../components/stat-block-panel.js";
 import { useBestiaryContext } from "../contexts/bestiary-context.js";
 import { useSidePanelContext } from "../contexts/side-panel-context.js";