feat: US-001 — scaffold NeuralDesk Electron + React app

- electron-forge 7 + Vite plugin (vite-typescript template)
- React 19 + TypeScript 5 strict mode
- TanStack Router with file-based routing (4 routes: /, /timeline, /tasks, /projects)
- Tailwind CSS 3 + PostCSS with Figma design tokens (sidebar, primary, muted)
- Framer Motion, Lucide React, shadcn/ui utilities (cn, CVA, clsx, twMerge)
- AppShell layout: 240px sidebar with collapse toggle, active route highlighting
- Vite configs use .mts extension to avoid ESM/CJS conflict with electron-forge
- Full package build verified (linux x64)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/renderer/globals.css

@@ -0,0 +1,48 @@
+@tailwind base;
+@tailwind components;
+@tailwind utilities;
+
+@layer base {
+  :root {
+    --background: 0 0% 100%;
+    --foreground: 0 0% 3.9%;
+    --primary: 0 0% 9%;
+    --primary-foreground: 0 0% 98%;
+    --secondary: 0 0% 96.1%;
+    --secondary-foreground: 0 0% 9%;
+    --muted: 0 0% 96.1%;
+    --muted-foreground: 0 0% 45.1%;
+    --border: 0 0% 89.8%;
+    --input: 0 0% 89.8%;
+    --ring: 0 0% 83.1%;
+    --radius: 0.5rem;
+
+    /* Sidebar tokens — matching Figma exactly */
+    --sidebar: 0 0% 98%;
+    --sidebar-border: 0 0% 89.8%;
+    --sidebar-accent: 0 0% 96.1%;
+    --sidebar-foreground: 0 0% 25.1%;
+  }
+
+  * {
+    border-color: hsl(var(--border));
+  }
+
+  body {
+    background-color: hsl(var(--background));
+    color: hsl(var(--foreground));
+    font-family: 'Geist', 'Inter', system-ui, sans-serif;
+    -webkit-font-smoothing: antialiased;
+    margin: 0;
+    overflow: hidden; /* Electron: no OS scrollbars */
+  }
+
+  #root {
+    height: 100vh;
+    width: 100vw;
+    display: flex;
+    overflow: hidden;
+  }
+}
+
+/* Geist font — loaded via CDN in index.html */