feat: add subjects and tasks API, hooks, and related types

- Implemented subjects API with functions for creating, updating, and retrieving subjects, including history and bibliography.
- Added tasks API for managing user tasks, including listing and marking tasks as completed.
- Created hooks for managing AI interactions, authentication, subjects, tasks, and metadata queries.
- Established query keys for caching and managing query states.
- Introduced Supabase client and environment variable management for better configuration.
- Defined types for database and domain models to ensure type safety across the application.

src/data/query/queryClient.ts

@@ -0,0 +1,14 @@
+import { QueryClient } from "@tanstack/react-query";
+
+export const queryClient = new QueryClient({
+  defaultOptions: {
+    queries: {
+      staleTime: 30_000,
+      refetchOnWindowFocus: false,
+      retry: (failureCount) => failureCount < 2,
+    },
+    mutations: {
+      retry: 0,
+    },
+  },
+});