feat: Step 1 - Project setup & smoke test

Initialize Next.js 16 (App Router) project with all core dependencies:
- Next.js, React 19, TypeScript configuration
- Mantine UI components (@mantine/core, @mantine/hooks)
- ATproto SDK for Bluesky integration
- SurrealDB client (updated to latest non-deprecated version)
- Vercel AI SDK with Google AI provider
- Deepgram SDK for voice-to-text
- React Three Fiber for 3D visualization
- UMAP.js for dimensionality reduction
- Magnitude test framework for E2E testing
- Playwright for browser automation

Created basic app structure with homepage displaying "Ponderants" text.
Configured magnitude.config.ts for testing framework.
Added .example.env with all required environment variables.

Test: Smoke test verifies app boots and renders homepage.
Status: ✓ Test passed (8.4s)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

postcss.config.mjs

@@ -0,0 +1,17 @@
+/** @type {import('postcss-load-config').Config} */
+const config = {
+  plugins: {
+    'postcss-preset-mantine': {},
+    'postcss-simple-vars': {
+      variables: {
+        'mantine-breakpoint-xs': '36em',
+        'mantine-breakpoint-sm': '48em',
+        'mantine-breakpoint-md': '62em',
+        'mantine-breakpoint-lg': '75em',
+        'mantine-breakpoint-xl': '88em',
+      },
+    },
+  },
+};
+
+export default config;