feat: initial FitCoach Pro lead management app

Next.js 16 app with full CRUD lead management:
- REST API (/api/leads) with GET (pagination), POST, PUT, DELETE (soft delete)
- Zod validation (server + client), Supabase (PostgreSQL)
- Responsive UI: leads table (desktop) + cards (mobile), modal form, toast notifications
- 43 tests (Vitest + React Testing Library): validation, components, pagination
- Docker setup (multi-stage build, health check)
- Supabase migration + 15 seed leads
- Documentation (CLAUDE.md, README, API docs)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

vitest.config.ts

@@ -0,0 +1,34 @@
+import { defineConfig } from "vitest/config";
+import react from "@vitejs/plugin-react";
+import path from "path";
+
+export default defineConfig({
+  plugins: [react()],
+  test: {
+    environment: "jsdom",
+    setupFiles: ["./src/test/setup.ts"],
+    include: ["src/**/*.test.{ts,tsx}"],
+    coverage: {
+      provider: "v8",
+      reporter: ["text", "json", "html"],
+      include: ["src/**/*.{ts,tsx}"],
+      exclude: [
+        "src/test/**",
+        "src/**/*.test.{ts,tsx}",
+        "src/**/*.d.ts",
+        "src/app/layout.tsx",
+      ],
+      thresholds: {
+        statements: 80,
+        branches: 80,
+        functions: 80,
+        lines: 80,
+      },
+    },
+  },
+  resolve: {
+    alias: {
+      "@": path.resolve(__dirname, "./src"),
+    },
+  },
+});