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/Framework/Core/Services/LinkValidatorTest.php

@@ -0,0 +1,381 @@
+<?php
+
+declare(strict_types=1);
+
+use App\Framework\Core\Services\LinkValidator;
+use App\Framework\Core\ValueObjects\AccessibleLink;
+use App\Framework\Core\ValueObjects\HtmlLink;
+use App\Framework\Core\ValueObjects\LinkRel;
+use App\Framework\Core\ValueObjects\LinkTarget;
+
+// Helper function to check if array contains string (case-insensitive)
+function arrayContainsString(array $array, string $needle): bool
+{
+    $needleLower = strtolower($needle);
+    foreach ($array as $item) {
+        if (str_contains(strtolower($item), $needleLower)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+describe('LinkValidator Service', function () {
+    beforeEach(function () {
+        $this->validator = new LinkValidator();
+    });
+
+    describe('Security Validation', function () {
+        it('detects missing noopener on external blank links', function () {
+            $link = new HtmlLink(
+                href: 'https://external.com',
+                text: 'External',
+                target: LinkTarget::BLANK,
+                rel: [] // Missing noopener
+            );
+
+            $result = $this->validator->validate($link);
+
+            expect($result->isValid)->toBeFalse()
+                ->and($result->hasErrors())->toBeTrue()
+                ->and(arrayContainsString($result->errors, 'noopener'))->toBeTrue();
+        });
+
+        it('passes external blank link with proper security', function () {
+            $link = HtmlLink::external('https://external.com', 'External');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->isValid)->toBeTrue()
+                ->and($result->hasErrors())->toBeFalse();
+        });
+
+        it('warns about javascript hrefs', function () {
+            $link = HtmlLink::create('javascript:alert("test")', 'Bad Link');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->isValid)->toBeFalse()
+                ->and(arrayContainsString($result->errors, 'JavaScript hrefs'))->toBeTrue();
+        });
+
+        it('warns about download without filename', function () {
+            $link = HtmlLink::download('/file.pdf', 'Download');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasFilenameWarning = arrayContainsString($result->errors, 'filename')
+                || arrayContainsString($result->warnings, 'filename')
+                || arrayContainsString($result->suggestions, 'filename');
+
+            expect($hasFilenameWarning)->toBeTrue();
+        });
+    });
+
+    describe('Accessibility Validation', function () {
+        it('warns about generic link text', function () {
+            $link = HtmlLink::create('/page', 'Click here');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasGenericText = arrayContainsString($result->errors, 'generic link text')
+                || arrayContainsString($result->warnings, 'generic link text')
+                || arrayContainsString($result->suggestions, 'generic link text');
+
+            expect($hasGenericText)->toBeTrue();
+        });
+
+        it('suggests indicating new window for external links', function () {
+            $link = HtmlLink::external('https://external.com', 'External');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasNewWindowSuggestion = arrayContainsString($result->errors, 'new window')
+                || arrayContainsString($result->warnings, 'new window')
+                || arrayContainsString($result->suggestions, 'new window');
+
+            expect($hasNewWindowSuggestion)->toBeTrue();
+        });
+
+        it('warns about very short link text', function () {
+            $link = HtmlLink::create('/page', 'X');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasTooShortWarning = arrayContainsString($result->errors, 'too short')
+                || arrayContainsString($result->warnings, 'too short')
+                || arrayContainsString($result->suggestions, 'too short');
+
+            expect($hasTooShortWarning)->toBeTrue();
+        });
+
+        it('suggests improvements for disabled links', function () {
+            $link = HtmlLink::create('/page', 'Page')->withDisabled(true);
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasAccessibleLinkSuggestion = arrayContainsString($result->errors, 'AccessibleLink')
+                || arrayContainsString($result->warnings, 'AccessibleLink')
+                || arrayContainsString($result->suggestions, 'AccessibleLink');
+
+            expect($hasAccessibleLinkSuggestion)->toBeTrue();
+        });
+    });
+
+    describe('SEO Validation', function () {
+        it('warns about nofollow on internal links', function () {
+            $link = new HtmlLink(
+                href: '/internal-page',
+                text: 'Internal',
+                rel: [LinkRel::NOFOLLOW]
+            );
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasInternalLinkWarning = arrayContainsString($result->errors, 'Internal link')
+                || arrayContainsString($result->warnings, 'Internal link')
+                || arrayContainsString($result->suggestions, 'Internal link');
+
+            expect($hasInternalLinkWarning)->toBeTrue();
+        });
+
+        it('suggests pagination rels for pagination URLs', function () {
+            $link = HtmlLink::create('/posts?page=2', 'Page 2');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasPaginationSuggestion = arrayContainsString($result->errors, 'pagination')
+                || arrayContainsString($result->warnings, 'pagination')
+                || arrayContainsString($result->suggestions, 'pagination');
+
+            expect($hasPaginationSuggestion)->toBeTrue();
+        });
+
+        it('warns about relative canonical URLs', function () {
+            $link = new HtmlLink(
+                href: '/canonical-page',
+                text: 'Canonical',
+                rel: [LinkRel::CANONICAL]
+            );
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasAbsoluteUrlWarning = arrayContainsString($result->errors, 'absolute URL')
+                || arrayContainsString($result->warnings, 'absolute URL')
+                || arrayContainsString($result->suggestions, 'absolute URL');
+
+            expect($hasAbsoluteUrlWarning)->toBeTrue();
+        });
+    });
+
+    describe('AccessibleLink Validation', function () {
+        it('validates ARIA attributes', function () {
+            $link = new AccessibleLink(
+                baseLink: HtmlLink::create('/page', 'Page'),
+                ariaCurrent: true,
+                ariaDisabled: true // Conflicting states
+            );
+
+            $result = $this->validator->validateAccessible($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasConflictingStatesWarning = arrayContainsString($result->errors, 'conflicting states')
+                || arrayContainsString($result->warnings, 'conflicting states')
+                || arrayContainsString($result->suggestions, 'conflicting states');
+
+            expect($hasConflictingStatesWarning)->toBeTrue();
+        });
+
+        it('warns about aria-hidden without tabindex=-1', function () {
+            $link = new AccessibleLink(
+                baseLink: HtmlLink::create('/page', 'Page'),
+                ariaHidden: true,
+                tabindex: 0
+            );
+
+            $result = $this->validator->validateAccessible($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasTabindexWarning = arrayContainsString($result->errors, 'tabindex="-1"')
+                || arrayContainsString($result->warnings, 'tabindex="-1"')
+                || arrayContainsString($result->suggestions, 'tabindex="-1"');
+
+            expect($hasTabindexWarning)->toBeTrue();
+        });
+
+        it('suggests tabindex=-1 for current page', function () {
+            $link = new AccessibleLink(
+                baseLink: HtmlLink::create('/current', 'Current'),
+                ariaCurrent: true,
+                tabindex: 0
+            );
+
+            $result = $this->validator->validateAccessible($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasCurrentPageSuggestion = arrayContainsString($result->errors, 'Current page link')
+                || arrayContainsString($result->warnings, 'Current page link')
+                || arrayContainsString($result->suggestions, 'Current page link');
+
+            expect($hasCurrentPageSuggestion)->toBeTrue();
+        });
+    });
+
+    describe('Best Practices Validation', function () {
+        it('warns about empty href', function () {
+            $link = HtmlLink::create('#', 'Empty');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasWarnings())->toBeTrue();
+
+            $hasEmptyHrefWarning = arrayContainsString($result->errors, 'empty or hash-only')
+                || arrayContainsString($result->warnings, 'empty or hash-only')
+                || arrayContainsString($result->suggestions, 'empty or hash-only');
+
+            expect($hasEmptyHrefWarning)->toBeTrue();
+        });
+
+        it('suggests shortening very long link text', function () {
+            $longText = str_repeat('Very long link text ', 10);
+            $link = HtmlLink::create('/page', $longText);
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasVeryLongSuggestion = arrayContainsString($result->errors, 'very long')
+                || arrayContainsString($result->warnings, 'very long')
+                || arrayContainsString($result->suggestions, 'very long');
+
+            expect($hasVeryLongSuggestion)->toBeTrue();
+        });
+
+        it('suggests file type indication for downloads', function () {
+            $link = HtmlLink::download('/document', 'Download Document');
+
+            $result = $this->validator->validate($link);
+
+            expect($result->hasSuggestions())->toBeTrue();
+
+            $hasFileTypeSuggestion = arrayContainsString($result->errors, 'file type')
+                || arrayContainsString($result->warnings, 'file type')
+                || arrayContainsString($result->suggestions, 'file type');
+
+            expect($hasFileTypeSuggestion)->toBeTrue();
+        });
+    });
+
+    describe('Batch Validation', function () {
+        it('validates multiple links', function () {
+            $links = [
+                HtmlLink::create('https://example.com', 'Example'),
+                HtmlLink::external('https://external.com', 'External'),
+                HtmlLink::create('/internal', 'Internal'),
+            ];
+
+            $results = $this->validator->validateBatch($links);
+
+            expect($results)->toHaveCount(3)
+                ->and($results[0])->toBeInstanceOf(\App\Framework\Core\ValueObjects\LinkValidationResult::class);
+        });
+
+        it('generates validation summary', function () {
+            $results = [
+                \App\Framework\Core\ValueObjects\LinkValidationResult::valid(),
+                \App\Framework\Core\ValueObjects\LinkValidationResult::invalid(['Error 1']),
+                \App\Framework\Core\ValueObjects\LinkValidationResult::valid(),
+            ];
+
+            $summary = $this->validator->getSummary($results);
+
+            expect($summary['total_links'])->toBe(3)
+                ->and($summary['valid_links'])->toBe(2)
+                ->and($summary['invalid_links'])->toBe(1)
+                ->and($summary['total_errors'])->toBe(1)
+                ->and($summary['validation_rate'])->toBe(66.67);
+        });
+    });
+
+    describe('Strict Mode', function () {
+        it('treats warnings as errors in strict mode', function () {
+            $strictValidator = new LinkValidator(strictMode: true);
+
+            $link = HtmlLink::download('/file.pdf', 'Download'); // Has warnings
+
+            $result = $strictValidator->validate($link);
+
+            expect($result->isValid)->toBeFalse() // Warnings fail in strict mode
+                ->and($result->hasWarnings())->toBeTrue();
+        });
+    });
+});
+
+describe('LinkValidationResult Value Object', function () {
+    it('can create valid result', function () {
+        $result = \App\Framework\Core\ValueObjects\LinkValidationResult::valid();
+
+        expect($result->isValid)->toBeTrue()
+            ->and($result->hasErrors())->toBeFalse();
+    });
+
+    it('can create invalid result', function () {
+        $result = \App\Framework\Core\ValueObjects\LinkValidationResult::invalid(
+            ['Error 1', 'Error 2'],
+            ['Warning 1']
+        );
+
+        expect($result->isValid)->toBeFalse()
+            ->and($result->hasErrors())->toBeTrue()
+            ->and($result->hasWarnings())->toBeTrue()
+            ->and($result->getIssueCount())->toBe(3);
+    });
+
+    it('can get all issues combined', function () {
+        $result = new \App\Framework\Core\ValueObjects\LinkValidationResult(
+            isValid: false,
+            errors: ['Error 1'],
+            warnings: ['Warning 1', 'Warning 2']
+        );
+
+        $issues = $result->getAllIssues();
+
+        expect($issues)->toHaveCount(3)
+            ->and($issues)->toContain('Error 1')
+            ->and($issues)->toContain('Warning 1');
+    });
+
+    it('converts to array for logging', function () {
+        $result = \App\Framework\Core\ValueObjects\LinkValidationResult::invalid(
+            ['Error 1'],
+            ['Warning 1']
+        );
+
+        $array = $result->toArray();
+
+        expect($array)->toHaveKey('is_valid')
+            ->and($array)->toHaveKey('errors')
+            ->and($array)->toHaveKey('warnings')
+            ->and($array['error_count'])->toBe(1)
+            ->and($array['warning_count'])->toBe(1);
+    });
+});