Consolidate hooks

* Hooks are in multiple places in the codebase and some camelCase, some snake-case. This PR relocates them all to the lib/hooks folder and normalizes camelCase naming. Settled on src/client/lib/hooks for the location since most of them were already there.

  - Refactor/move useTheme.ts from client/src/lib to client/src/lib/hooks
  - Refactor/move useToast.ts from client/src/hooks/ to client/src/lib/hooks/useToast.ts
  - Removed client/src/hooks

client/src/components/__tests__/Sidebar.test.tsx

@@ -7,7 +7,7 @@ import { InspectorConfig } from "@/lib/configurationTypes";
 import { TooltipProvider } from "@/components/ui/tooltip";
 
 // Mock theme hook
-jest.mock("../../lib/useTheme", () => ({
+jest.mock("../../lib/hooks/useTheme", () => ({
   __esModule: true,
   default: () => ["light", jest.fn()],
 }));