feat(web): scaffold Next.js 16 dashboard with design system and auth client (#82)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/design-tokens/src/colors.ts

@@ -0,0 +1,91 @@
+/**
+ * Mosaic Stack color palette.
+ * Deep blue-grays with blue/purple/teal accents.
+ */
+
+export const colors = {
+  /** Neutral blue-gray scale */
+  gray: {
+    50: '#f0f2f5',
+    100: '#dce0e8',
+    200: '#b8c0cc',
+    300: '#8e99a9',
+    400: '#6b7a8d',
+    500: '#4e5d70',
+    600: '#3b4859',
+    700: '#2a3544',
+    800: '#1c2433',
+    900: '#111827',
+    950: '#0a0f1a',
+  },
+
+  /** Primary — blue */
+  blue: {
+    50: '#eff4ff',
+    100: '#dae5ff',
+    200: '#bdd1ff',
+    300: '#8fb4ff',
+    400: '#5b8bff',
+    500: '#3b6cf7',
+    600: '#2551e0',
+    700: '#1d40c0',
+    800: '#1e369c',
+    900: '#1e317b',
+    950: '#162050',
+  },
+
+  /** Accent — purple */
+  purple: {
+    50: '#f3f0ff',
+    100: '#e7dfff',
+    200: '#d2c3ff',
+    300: '#b49aff',
+    400: '#9466ff',
+    500: '#7c3aed',
+    600: '#6d28d9',
+    700: '#5b21b6',
+    800: '#4c1d95',
+    900: '#3b1578',
+    950: '#230d4d',
+  },
+
+  /** Accent — teal */
+  teal: {
+    50: '#effcf9',
+    100: '#d0f7ef',
+    200: '#a4eddf',
+    300: '#6fddcb',
+    400: '#3ec5b2',
+    500: '#25aa99',
+    600: '#1c897e',
+    700: '#1b6e66',
+    800: '#1a5853',
+    900: '#194945',
+    950: '#082d2b',
+  },
+
+  /** Semantic */
+  success: '#22c55e',
+  warning: '#f59e0b',
+  error: '#ef4444',
+  info: '#3b82f6',
+
+  /** Surface — dark theme defaults */
+  surface: {
+    background: '#0a0f1a',
+    card: '#111827',
+    elevated: '#1c2433',
+    overlay: 'rgba(0, 0, 0, 0.6)',
+    border: '#2a3544',
+  },
+
+  /** Text */
+  text: {
+    primary: '#f0f2f5',
+    secondary: '#8e99a9',
+    muted: '#6b7a8d',
+    inverse: '#0a0f1a',
+  },
+} as const;
+
+export type Colors = typeof colors;