feat(Production): Complete production deployment infrastructure

- Add comprehensive health check system with multiple endpoints
- Add Prometheus metrics endpoint
- Add production logging configurations (5 strategies)
- Add complete deployment documentation suite:
  * QUICKSTART.md - 30-minute deployment guide
  * DEPLOYMENT_CHECKLIST.md - Printable verification checklist
  * DEPLOYMENT_WORKFLOW.md - Complete deployment lifecycle
  * PRODUCTION_DEPLOYMENT.md - Comprehensive technical reference
  * production-logging.md - Logging configuration guide
  * ANSIBLE_DEPLOYMENT.md - Infrastructure as Code automation
  * README.md - Navigation hub
  * DEPLOYMENT_SUMMARY.md - Executive summary
- Add deployment scripts and automation
- Add DEPLOYMENT_PLAN.md - Concrete plan for immediate deployment
- Update README with production-ready features

All production infrastructure is now complete and ready for deployment.

tests/Unit/Domain/SmartLink/ValueObjects/ShortCodeTest.php

@@ -0,0 +1,118 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Domain\SmartLink\ValueObjects\ShortCode;
+
+describe('ShortCode Value Object', function () {
+    it('creates valid short code', function () {
+        $code = ShortCode::fromString('abc123');
+
+        expect($code->toString())->toBe('abc123');
+    });
+
+    it('creates short code with valid length 6', function () {
+        $code = ShortCode::fromString('abcdef');
+        expect($code->toString())->toBe('abcdef');
+    });
+
+    it('creates short code with valid length 7', function () {
+        $code = ShortCode::fromString('abc1234');
+        expect($code->toString())->toBe('abc1234');
+    });
+
+    it('creates short code with valid length 8', function () {
+        $code = ShortCode::fromString('abc12345');
+        expect($code->toString())->toBe('abc12345');
+    });
+
+    it('throws exception for too short code', function () {
+        expect(fn() => ShortCode::fromString('abc12'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode must be between 6 and 8 characters');
+    });
+
+    it('throws exception for too long code', function () {
+        expect(fn() => ShortCode::fromString('abc123456'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode must be between 6 and 8 characters');
+    });
+
+    it('accepts lowercase alphanumeric characters', function () {
+        $code = ShortCode::fromString('abc123');
+        expect($code->toString())->toBe('abc123');
+    });
+
+    it('accepts uppercase alphanumeric characters', function () {
+        $code = ShortCode::fromString('ABC123');
+        expect($code->toString())->toBe('ABC123');
+    });
+
+    it('accepts mixed case alphanumeric characters', function () {
+        $code = ShortCode::fromString('aBcDeF');
+        expect($code->toString())->toBe('aBcDeF');
+    });
+
+    it('rejects dash characters', function () {
+        expect(fn() => ShortCode::fromString('abc-12'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode can only contain alphanumeric characters');
+    });
+
+    it('rejects underscore characters', function () {
+        expect(fn() => ShortCode::fromString('abc_12'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode can only contain alphanumeric characters');
+    });
+
+    it('rejects space characters', function () {
+        expect(fn() => ShortCode::fromString('abc 12'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode can only contain alphanumeric characters');
+    });
+
+    it('rejects special characters', function () {
+        expect(fn() => ShortCode::fromString('abc@12'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode can only contain alphanumeric characters');
+    });
+
+    it('rejects dot characters', function () {
+        expect(fn() => ShortCode::fromString('abc.12'))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode can only contain alphanumeric characters');
+    });
+
+    it('rejects too short code', function () {
+        // Empty string triggers length validation, not empty check
+        expect(fn() => ShortCode::fromString(''))
+            ->toThrow(\InvalidArgumentException::class, 'ShortCode must be between 6 and 8 characters');
+    });
+
+    it('compares short codes correctly', function () {
+        $code1 = ShortCode::fromString('abc123');
+        $code2 = ShortCode::fromString('abc123');
+        $code3 = ShortCode::fromString('xyz789');
+
+        expect($code1->equals($code2))->toBeTrue();
+        expect($code1->equals($code3))->toBeFalse();
+    });
+
+    it('converts to string', function () {
+        $code = ShortCode::fromString('test12');
+
+        expect($code->toString())->toBe('test12');
+        expect((string) $code)->toBe('test12');
+    });
+
+    it('generates random short codes of length 6', function () {
+        $code = ShortCode::generate(6);
+
+        expect($code->toString())->toHaveLength(6);
+        expect($code->toString())->toMatch('/^[a-zA-Z0-9]{6}$/');
+    });
+
+    it('generates unique codes on multiple calls', function () {
+        $codes = [];
+        for ($i = 0; $i < 10; $i++) {
+            $codes[] = ShortCode::generate(6)->toString();
+        }
+
+        $uniqueCodes = array_unique($codes);
+        // With 62 possible characters and 6 positions, duplicates are extremely unlikely
+        expect(count($uniqueCodes))->toBeGreaterThan(8);
+    });
+});