feat: comprehensive security and architecture improvements

- Add Zod validation schemas with strong password requirements (12+ chars, complexity)
- Implement rate limiting for authentication endpoints (registration, password reset)
- Remove duplicate MetricCard component, consolidate to ui/metric-card.tsx
- Update README.md to use pnpm commands consistently
- Enhance authentication security with 12-round bcrypt hashing
- Add comprehensive input validation for all API endpoints
- Fix security vulnerabilities in user registration and password reset flows

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

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

server.ts

@@ -19,11 +19,11 @@ app.prepare().then(() => {
   // Validate and log environment configuration
   const envValidation = validateEnv();
   if (!envValidation.valid) {
-    console.error('[Environment] Validation errors:', envValidation.errors);
+    console.error("[Environment] Validation errors:", envValidation.errors);
   }
-  
+
   logEnvConfig();
-  
+
   // Get scheduler configuration
   const config = getSchedulerConfig();