feat: dark-tech UI redesign + markdown patch cards

Redesign the frontend with a dark-tech theme: add Tailwind + PostCSS,
design tokens, and shadcn-style primitives (Button/Card/Input/Dialog/
DropdownMenu/Tabs/ScrollArea/etc.); restyle the app shell, navigation,
sidebar tree, content view, markdown rendering, editors, modals and
settings panels. Behavior/props unchanged; Font Awesome replaced with
lucide-react.

Add the patch cards feature UI: patch-queries hooks and a PatchCards
component rendered below the markdown body, with an Add Patch button
and create/edit dialog.

Fix tree expandability: folders with an index page now expand on name
click (and navigate), and the chevron+folder icon is one larger toggle.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/index.js

@@ -3,6 +3,7 @@ import ReactDOM from "react-dom/client";
 import App from "./App";
 import AuthProvider, {AuthContext} from "./AuthProvider";
 import "bulma/css/bulma.min.css";
+import "./globals.css";
 import {QueryClient, QueryClientProvider} from "@tanstack/react-query"
 import ConfigProvider from "./ConfigProvider";
 import ControlledReactQueryDevtools from "./components/Debug/ControlledReactQueryDevtools";