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/Logging/SamplingLogHandlerTest.php

@@ -0,0 +1,120 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit\Framework\Logging;
+
+use App\Framework\Logging\Handlers\SamplingLogHandler;
+use App\Framework\Logging\LogHandler;
+use App\Framework\Logging\LogLevel;
+use App\Framework\Logging\LogRecord;
+use App\Framework\Logging\Sampling\SamplingConfig;
+use App\Framework\Logging\ValueObjects\LogContext;
+use PHPUnit\Framework\TestCase;
+
+final class SamplingLogHandlerTest extends TestCase
+{
+    public function test_samples_logs_based_on_config(): void
+    {
+        $inner = $this->createMock(LogHandler::class);
+
+        // Config: 100% ERROR, 0% INFO
+        $config = SamplingConfig::custom([
+            'ERROR' => 1.0,
+            'INFO' => 0.0,
+        ]);
+
+        $handler = new SamplingLogHandler($inner, $config);
+
+        // ERROR sollte durchkommen
+        $inner->expects($this->once())->method('handle');
+        $handler->handle($this->createLogRecord('error', LogLevel::ERROR));
+
+        // INFO sollte gedroppt werden
+        $handler->handle($this->createLogRecord('info', LogLevel::INFO));
+
+        $this->assertEquals(1, $handler->getAcceptedCount());
+        $this->assertEquals(1, $handler->getDroppedCount());
+    }
+
+    public function test_never_samples_critical_levels(): void
+    {
+        $inner = $this->createMock(LogHandler::class);
+
+        $config = SamplingConfig::production();
+        $handler = new SamplingLogHandler($inner, $config);
+
+        $criticalLevels = [
+            LogLevel::ERROR,
+            LogLevel::CRITICAL,
+            LogLevel::ALERT,
+            LogLevel::EMERGENCY,
+        ];
+
+        $inner->expects($this->exactly(count($criticalLevels)))
+            ->method('handle');
+
+        foreach ($criticalLevels as $level) {
+            $handler->handle($this->createLogRecord('test', $level));
+        }
+
+        $this->assertEquals(count($criticalLevels), $handler->getAcceptedCount());
+        $this->assertEquals(0, $handler->getDroppedCount());
+    }
+
+    public function test_tracks_dropped_by_level(): void
+    {
+        $inner = $this->createMock(LogHandler::class);
+
+        $config = SamplingConfig::custom(['INFO' => 0.0]);
+        $handler = new SamplingLogHandler($inner, $config);
+
+        for ($i = 0; $i < 10; $i++) {
+            $handler->handle($this->createLogRecord('info', LogLevel::INFO));
+        }
+
+        $dropped = $handler->getDroppedByLevel();
+
+        $this->assertArrayHasKey('INFO', $dropped);
+        $this->assertEquals(10, $dropped['INFO']);
+    }
+
+    public function test_calculates_drop_rate(): void
+    {
+        $inner = $this->createMock(LogHandler::class);
+
+        $config = SamplingConfig::custom(['INFO' => 0.5]);
+        $handler = new SamplingLogHandler($inner, $config);
+
+        // Simulate: sollte ca. 50% droppen
+        // Für deterministische Tests mocken wir mt_rand nicht,
+        // aber prüfen nur dass Drop-Rate berechnet wird
+
+        $this->assertEquals(0.0, $handler->getDropRate()); // Noch keine Logs
+    }
+
+    public function test_health_check(): void
+    {
+        $inner = $this->createMock(LogHandler::class);
+        $handler = new SamplingLogHandler($inner, SamplingConfig::production());
+
+        $health = $handler->check();
+
+        $this->assertEquals(\App\Framework\Health\HealthStatus::HEALTHY, $health->status);
+        $this->assertArrayHasKey('accepted', $health->details);
+        $this->assertArrayHasKey('dropped', $health->details);
+    }
+
+    private function createLogRecord(
+        string $message = 'test',
+        LogLevel $level = LogLevel::INFO
+    ): LogRecord {
+        return new LogRecord(
+            level: $level,
+            message: $message,
+            channel: 'test',
+            context: LogContext::empty(),
+            timestamp: new \DateTimeImmutable()
+        );
+    }
+}