refactor(client): migrate state management from React Context to Jotai

Replace AuthProvider and SyncProvider with Jotai atoms for more granular
state management and better performance. This migration:

- Creates atoms for auth, sync, decks, cards, noteTypes, and study state
- Uses atomFamily for parameterized state (e.g., cards by deckId)
- Introduces StoreInitializer component for subscription initialization
- Updates all components and pages to use useAtomValue/useSetAtom
- Updates all tests to use Jotai Provider with createStore pattern

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

1 files changed, 0 insertions, 303 deletions

diff --git a/src/client/stores/sync.tsx b/src/client/stores/sync.tsx
deleted file mode 100644
index 9b46302..0000000
--- a/src/client/stores/sync.tsx
+++ /dev/null
@@ -1,303 +0,0 @@
-import {
-	createContext,
-	type ReactNode,
-	useCallback,
-	useContext,
-	useEffect,
-	useMemo,
-	useState,
-} from "react";
-import { apiClient } from "../api/client";
-import {
-	conflictResolver,
-	createPullService,
-	createPushService,
-	createSyncManager,
-	type SyncManagerEvent,
-	type SyncQueueState,
-	type SyncResult,
-	SyncStatus,
-	syncQueue,
-} from "../sync";
-import type {
-	ServerCard,
-	ServerDeck,
-	ServerNote,
-	ServerNoteFieldType,
-	ServerNoteFieldValue,
-	ServerNoteType,
-	ServerReviewLog,
-	SyncPullResult,
-} from "../sync/pull";
-import type { SyncPushData, SyncPushResult } from "../sync/push";
-
-export interface SyncState {
-	isOnline: boolean;
-	isSyncing: boolean;
-	pendingCount: number;
-	lastSyncAt: Date | null;
-	lastError: string | null;
-	status: SyncQueueState["status"];
-}
-
-export interface SyncActions {
-	sync: () => Promise<SyncResult>;
-}
-
-export type SyncContextValue = SyncState & SyncActions;
-
-const SyncContext = createContext<SyncContextValue | null>(null);
-
-export interface SyncProviderProps {
-	children: ReactNode;
-}
-
-interface PullResponse {
-	decks: Array<
-		Omit<ServerDeck, "createdAt" | "updatedAt" | "deletedAt"> & {
-			createdAt: string;
-			updatedAt: string;
-			deletedAt: string | null;
-		}
-	>;
-	cards: Array<
-		Omit<
-			ServerCard,
-			"due" | "lastReview" | "createdAt" | "updatedAt" | "deletedAt"
-		> & {
-			due: string;
-			lastReview: string | null;
-			createdAt: string;
-			updatedAt: string;
-			deletedAt: string | null;
-		}
-	>;
-	reviewLogs: Array<
-		Omit<ServerReviewLog, "reviewedAt"> & {
-			reviewedAt: string;
-		}
-	>;
-	noteTypes: Array<
-		Omit<ServerNoteType, "createdAt" | "updatedAt" | "deletedAt"> & {
-			createdAt: string;
-			updatedAt: string;
-			deletedAt: string | null;
-		}
-	>;
-	noteFieldTypes: Array<
-		Omit<ServerNoteFieldType, "createdAt" | "updatedAt" | "deletedAt"> & {
-			createdAt: string;
-			updatedAt: string;
-			deletedAt: string | null;
-		}
-	>;
-	notes: Array<
-		Omit<ServerNote, "createdAt" | "updatedAt" | "deletedAt"> & {
-			createdAt: string;
-			updatedAt: string;
-			deletedAt: string | null;
-		}
-	>;
-	noteFieldValues: Array<
-		Omit<ServerNoteFieldValue, "createdAt" | "updatedAt"> & {
-			createdAt: string;
-			updatedAt: string;
-		}
-	>;
-	currentSyncVersion: number;
-}
-
-async function pushToServer(data: SyncPushData): Promise<SyncPushResult> {
-	const res = await apiClient.authenticatedFetch("/api/sync/push", {
-		method: "POST",
-		headers: {
-			"Content-Type": "application/json",
-		},
-		body: JSON.stringify(data),
-	});
-
-	if (!res.ok) {
-		const errorBody = (await res.json().catch(() => ({}))) as {
-			error?: string;
-		};
-		throw new Error(errorBody.error || `Push failed with status ${res.status}`);
-	}
-
-	return res.json() as Promise<SyncPushResult>;
-}
-
-async function pullFromServer(
-	lastSyncVersion: number,
-): Promise<SyncPullResult> {
-	const res = await apiClient.authenticatedFetch(
-		`/api/sync/pull?lastSyncVersion=${lastSyncVersion}`,
-	);
-
-	if (!res.ok) {
-		const errorBody = (await res.json().catch(() => ({}))) as {
-			error?: string;
-		};
-		throw new Error(errorBody.error || `Pull failed with status ${res.status}`);
-	}
-
-	const data = (await res.json()) as PullResponse;
-
-	return {
-		decks: data.decks.map((d) => ({
-			...d,
-			createdAt: new Date(d.createdAt),
-			updatedAt: new Date(d.updatedAt),
-			deletedAt: d.deletedAt ? new Date(d.deletedAt) : null,
-		})),
-		cards: data.cards.map((c) => ({
-			...c,
-			due: new Date(c.due),
-			lastReview: c.lastReview ? new Date(c.lastReview) : null,
-			createdAt: new Date(c.createdAt),
-			updatedAt: new Date(c.updatedAt),
-			deletedAt: c.deletedAt ? new Date(c.deletedAt) : null,
-		})),
-		reviewLogs: data.reviewLogs.map((r) => ({
-			...r,
-			reviewedAt: new Date(r.reviewedAt),
-		})),
-		noteTypes: data.noteTypes.map((n) => ({
-			...n,
-			createdAt: new Date(n.createdAt),
-			updatedAt: new Date(n.updatedAt),
-			deletedAt: n.deletedAt ? new Date(n.deletedAt) : null,
-		})),
-		noteFieldTypes: data.noteFieldTypes.map((f) => ({
-			...f,
-			createdAt: new Date(f.createdAt),
-			updatedAt: new Date(f.updatedAt),
-			deletedAt: f.deletedAt ? new Date(f.deletedAt) : null,
-		})),
-		notes: data.notes.map((n) => ({
-			...n,
-			createdAt: new Date(n.createdAt),
-			updatedAt: new Date(n.updatedAt),
-			deletedAt: n.deletedAt ? new Date(n.deletedAt) : null,
-		})),
-		noteFieldValues: data.noteFieldValues.map((v) => ({
-			...v,
-			createdAt: new Date(v.createdAt),
-			updatedAt: new Date(v.updatedAt),
-		})),
-		currentSyncVersion: data.currentSyncVersion,
-	};
-}
-
-const pushService = createPushService({
-	syncQueue,
-	pushToServer,
-});
-
-const pullService = createPullService({
-	syncQueue,
-	pullFromServer,
-});
-
-const syncManager = createSyncManager({
-	syncQueue,
-	pushService,
-	pullService,
-	conflictResolver,
-});
-
-export function SyncProvider({ children }: SyncProviderProps) {
-	const [isOnline, setIsOnline] = useState(
-		typeof navigator !== "undefined" ? navigator.onLine : true,
-	);
-	const [isSyncing, setIsSyncing] = useState(false);
-	const [pendingCount, setPendingCount] = useState(0);
-	const [lastSyncAt, setLastSyncAt] = useState<Date | null>(null);
-	const [lastError, setLastError] = useState<string | null>(null);
-	const [status, setStatus] = useState<SyncQueueState["status"]>(
-		SyncStatus.Idle,
-	);
-
-	useEffect(() => {
-		syncManager.start();
-
-		const unsubscribeManager = syncManager.subscribe(
-			(event: SyncManagerEvent) => {
-				switch (event.type) {
-					case "online":
-						setIsOnline(true);
-						break;
-					case "offline":
-						setIsOnline(false);
-						break;
-					case "sync_start":
-						setIsSyncing(true);
-						setLastError(null);
-						setStatus(SyncStatus.Syncing);
-						break;
-					case "sync_complete":
-						setIsSyncing(false);
-						setLastSyncAt(new Date());
-						setStatus(SyncStatus.Idle);
-						break;
-					case "sync_error":
-						setIsSyncing(false);
-						setLastError(event.error);
-						setStatus(SyncStatus.Error);
-						break;
-				}
-			},
-		);
-
-		const unsubscribeQueue = syncQueue.subscribe((state: SyncQueueState) => {
-			setPendingCount(state.pendingCount);
-			if (state.lastSyncAt) {
-				setLastSyncAt(state.lastSyncAt);
-			}
-			if (state.lastError) {
-				setLastError(state.lastError);
-			}
-			setStatus(state.status);
-		});
-
-		// Initialize state from queue
-		syncQueue.getState().then((state) => {
-			setPendingCount(state.pendingCount);
-			setLastSyncAt(state.lastSyncAt);
-			setLastError(state.lastError);
-			setStatus(state.status);
-		});
-
-		return () => {
-			unsubscribeManager();
-			unsubscribeQueue();
-			syncManager.stop();
-		};
-	}, []);
-
-	const sync = useCallback(async () => {
-		return syncManager.sync();
-	}, []);
-
-	const value = useMemo<SyncContextValue>(
-		() => ({
-			isOnline,
-			isSyncing,
-			pendingCount,
-			lastSyncAt,
-			lastError,
-			status,
-			sync,
-		}),
-		[isOnline, isSyncing, pendingCount, lastSyncAt, lastError, status, sync],
-	);
-
-	return <SyncContext.Provider value={value}>{children}</SyncContext.Provider>;
-}
-
-export function useSync(): SyncContextValue {
-	const context = useContext(SyncContext);
-	if (!context) {
-		throw new Error("useSync must be used within a SyncProvider");
-	}
-	return context;
-}