Initial project setup for PhaseFlow

Set up Next.js 16 project with TypeScript for a training decision app
that integrates menstrual cycle phases with Garmin biometrics for
Hashimoto's thyroiditis management.

Stack: Next.js 16, React 19, Tailwind/shadcn, PocketBase, Drizzle,
Zod, Resend, Vitest, Biome, Lefthook, Nix dev environment.

Includes:
- 7 page routes (dashboard, login, settings, calendar, history, plan)
- 12 API endpoints (garmin, user, cycle, calendar, overrides, cron)
- Core lib utilities (decision engine, cycle phases, nutrition, ICS)
- Type definitions and component scaffolding
- Python script for Garmin token bootstrapping
- Initial unit tests for cycle utilities

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/app/page.tsx

@@ -0,0 +1,28 @@
+// ABOUTME: Main dashboard page for PhaseFlow.
+// ABOUTME: Displays today's training decision, biometrics, and quick actions.
+export default function Dashboard() {
+  return (
+    <div className="min-h-screen bg-zinc-50 dark:bg-black">
+      <header className="border-b bg-white dark:bg-zinc-900 px-6 py-4">
+        <div className="container mx-auto flex justify-between items-center">
+          <h1 className="text-xl font-bold">PhaseFlow</h1>
+          <a
+            href="/settings"
+            className="text-sm text-zinc-600 hover:text-zinc-900"
+          >
+            Settings
+          </a>
+        </div>
+      </header>
+
+      <main className="container mx-auto p-6">
+        <div className="text-center py-12">
+          <p className="text-zinc-500">Dashboard placeholder</p>
+          <p className="text-sm text-zinc-400 mt-2">
+            Connect your Garmin and set your period date to get started.
+          </p>
+        </div>
+      </main>
+    </div>
+  );
+}