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__/player-character-section.test.tsx

@@ -33,32 +33,6 @@ beforeAll(() => {
 
 afterEach(cleanup);
 
-vi.mock("../../persistence/encounter-storage.js", () => ({
-	loadEncounter: () => null,
-	saveEncounter: () => {},
-}));
-
-vi.mock("../../persistence/player-character-storage.js", () => ({
-	loadPlayerCharacters: () => [],
-	savePlayerCharacters: () => {},
-}));
-
-vi.mock("../../adapters/bestiary-cache.js", () => ({
-	loadAllCachedCreatures: () => Promise.resolve(new Map()),
-	isSourceCached: () => Promise.resolve(false),
-	cacheSource: () => Promise.resolve(),
-	getCachedSources: () => Promise.resolve([]),
-	clearSource: () => Promise.resolve(),
-	clearAll: () => Promise.resolve(),
-}));
-
-vi.mock("../../adapters/bestiary-index-adapter.js", () => ({
-	loadBestiaryIndex: () => ({ sources: {}, creatures: [] }),
-	getAllSourceCodes: () => [],
-	getDefaultFetchUrl: () => "",
-	getSourceDisplayName: (code: string) => code,
-}));
-
 function renderSection() {
 	const ref = createRef<PlayerCharacterSectionHandle>();
 	const result = render(<PlayerCharacterSection ref={ref} />, {