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/Entities/SmartLinkTest.php

@@ -0,0 +1,209 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Domain\SmartLink\Entities\SmartLink;
+use App\Domain\SmartLink\Enums\LinkStatus;
+use App\Domain\SmartLink\Enums\LinkType;
+use App\Domain\SmartLink\ValueObjects\LinkTitle;
+use App\Domain\SmartLink\ValueObjects\ShortCode;
+use App\Framework\DateTime\SystemClock;
+
+describe('SmartLink Entity', function () {
+    beforeEach(function () {
+        $this->clock = new SystemClock();
+        $this->shortCode = ShortCode::fromString('abc123');
+        $this->title = LinkTitle::fromString('My Smart Link');
+    });
+
+    describe('creation', function () {
+        it('creates smart link with required fields', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            expect($link->shortCode->toString())->toBe('abc123');
+            expect($link->type)->toBe(LinkType::RELEASE);
+            expect($link->title->toString())->toBe('My Smart Link');
+            expect($link->status)->toBe(LinkStatus::DRAFT);
+            expect($link->userId)->toBeNull();
+            expect($link->coverImageUrl)->toBeNull();
+        });
+
+        it('creates smart link with user ID', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title,
+                userId: 'user123'
+            );
+
+            expect($link->userId)->toBe('user123');
+            expect($link->isOwnedBy('user123'))->toBeTrue();
+        });
+
+        it('creates smart link with cover image', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title,
+                coverImageUrl: 'https://example.com/cover.jpg'
+            );
+
+            expect($link->coverImageUrl)->toBe('https://example.com/cover.jpg');
+        });
+
+        it('starts in DRAFT status', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            expect($link->status)->toBe(LinkStatus::DRAFT);
+            expect($link->isActive())->toBeFalse();
+        });
+    });
+
+    describe('status transitions', function () {
+        it('transitions from DRAFT to ACTIVE', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            $activeLink = $link->withStatus(LinkStatus::ACTIVE);
+
+            expect($activeLink->status)->toBe(LinkStatus::ACTIVE);
+            expect($activeLink->isActive())->toBeTrue();
+        });
+
+        it('transitions from ACTIVE to PAUSED', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            )->withStatus(LinkStatus::ACTIVE);
+
+            $pausedLink = $link->withStatus(LinkStatus::PAUSED);
+
+            expect($pausedLink->status)->toBe(LinkStatus::PAUSED);
+        });
+
+        it('throws exception for invalid transition', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            // Cannot transition directly from DRAFT to PAUSED
+            expect(fn() => $link->withStatus(LinkStatus::PAUSED))
+                ->toThrow(\DomainException::class);
+        });
+
+        it('throws exception for invalid transition from EXPIRED', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            )->withStatus(LinkStatus::ACTIVE)->withStatus(LinkStatus::EXPIRED);
+
+            // Cannot transition from EXPIRED to ACTIVE
+            expect(fn() => $link->withStatus(LinkStatus::ACTIVE))
+                ->toThrow(\DomainException::class);
+        });
+    });
+
+    describe('title updates', function () {
+        it('updates title', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            $newTitle = LinkTitle::fromString('Updated Title');
+            $updatedLink = $link->withTitle($newTitle);
+
+            expect($updatedLink->title->toString())->toBe('Updated Title');
+            expect($link->title->toString())->toBe('My Smart Link'); // Original unchanged
+        });
+    });
+
+    describe('access control', function () {
+        it('identifies active links as active', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            )->withStatus(LinkStatus::ACTIVE);
+
+            expect($link->isActive())->toBeTrue();
+            expect($link->canBeAccessed())->toBeTrue();
+        });
+
+        it('identifies draft links as not accessible', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            expect($link->canBeAccessed())->toBeFalse();
+        });
+
+        it('identifies paused links as not accessible', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            )->withStatus(LinkStatus::ACTIVE)->withStatus(LinkStatus::PAUSED);
+
+            expect($link->canBeAccessed())->toBeFalse();
+        });
+    });
+
+    describe('ownership', function () {
+        it('identifies owner correctly', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title,
+                userId: 'user123'
+            );
+
+            expect($link->isOwnedBy('user123'))->toBeTrue();
+            expect($link->isOwnedBy('user456'))->toBeFalse();
+            expect($link->isOwnedBy(null))->toBeFalse();
+        });
+
+        it('handles anonymous links', function () {
+            $link = SmartLink::create(
+                clock: $this->clock,
+                shortCode: $this->shortCode,
+                type: LinkType::RELEASE,
+                title: $this->title
+            );
+
+            expect($link->userId)->toBeNull();
+            expect($link->isOwnedBy('user123'))->toBeFalse();
+        });
+    });
+});