fix: Gitea Traefik routing and connection pool optimization

- Remove middleware reference from Gitea Traefik labels (caused routing issues)
- Optimize Gitea connection pool settings (MAX_IDLE_CONNS=30, authentication_timeout=180s)
- Add explicit service reference in Traefik labels
- Fix intermittent 504 timeouts by improving PostgreSQL connection handling

Fixes Gitea unreachability via git.michaelschiemer.de

src/Framework/ExceptionHandling/Correlation/ExceptionCorrelation.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\ExceptionHandling\Correlation;
+
+/**
+ * Exception Correlation
+ *
+ * Immutable value object representing correlation between exceptions.
+ */
+final readonly class ExceptionCorrelation
+{
+    /**
+     * @param string $correlationKey Correlation key (Request-ID, Session-ID, etc.)
+     * @param array<string> $exceptionIds Related exception IDs
+     * @param string|null $rootCauseId Root cause exception ID
+     */
+    public function __construct(
+        public string $correlationKey,
+        public array $exceptionIds = [],
+        public ?string $rootCauseId = null
+    ) {
+    }
+
+    /**
+     * Convert to array for serialization
+     *
+     * @return array<string, mixed>
+     */
+    public function toArray(): array
+    {
+        return [
+            'correlation_key' => $this->correlationKey,
+            'exception_ids' => $this->exceptionIds,
+            'root_cause_id' => $this->rootCauseId,
+        ];
+    }
+}
+

src/Framework/ExceptionHandling/Correlation/ExceptionCorrelationEngine.php

@@ -0,0 +1,131 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\ExceptionHandling\Correlation;
+
+use App\Framework\Cache\Cache;
+use App\Framework\Cache\CacheItem;
+use App\Framework\Cache\CacheKey;
+use App\Framework\Core\ValueObjects\Duration;
+use App\Framework\ExceptionHandling\Context\ExceptionContextData;
+use Throwable;
+
+/**
+ * Exception Correlation Engine
+ *
+ * Correlates related exceptions for root cause analysis.
+ */
+final readonly class ExceptionCorrelationEngine
+{
+    private const string CACHE_PREFIX = 'exception_correlation:';
+    private const int CACHE_TTL = 3600; // 1 hour
+
+    public function __construct(
+        private Cache $cache
+    ) {
+    }
+
+    /**
+     * Correlate exception with related exceptions
+     *
+     * @param Throwable $exception Exception to correlate
+     * @param ExceptionContextData|null $context Optional context
+     * @return ExceptionCorrelation Correlation data
+     */
+    public function correlate(Throwable $exception, ?ExceptionContextData $context = null): ExceptionCorrelation
+    {
+        $correlationKey = $this->extractCorrelationKey($context);
+        if ($correlationKey === null) {
+            return new ExceptionCorrelation(correlationKey: 'unknown');
+        }
+
+        $exceptionId = spl_object_id($exception);
+        $cacheKey = CacheKey::fromString(self::CACHE_PREFIX . $correlationKey);
+
+        // Get existing correlation
+        $existing = $this->getCorrelation($cacheKey);
+        $exceptionIds = $existing->exceptionIds;
+        $exceptionIds[] = (string) $exceptionId;
+
+        // First exception in correlation is root cause
+        $rootCauseId = $existing->rootCauseId ?? (string) $exceptionId;
+
+        $correlation = new ExceptionCorrelation(
+            correlationKey: $correlationKey,
+            exceptionIds: array_unique($exceptionIds),
+            rootCauseId: $rootCauseId
+        );
+
+        // Store correlation
+        $this->storeCorrelation($cacheKey, $correlation);
+
+        return $correlation;
+    }
+
+    /**
+     * Extract correlation key from context
+     */
+    private function extractCorrelationKey(?ExceptionContextData $context): ?string
+    {
+        if ($context === null) {
+            return null;
+        }
+
+        // Prefer Request-ID, then Session-ID, then User-ID
+        if ($context->requestId !== null) {
+            $requestId = is_string($context->requestId) ? $context->requestId : $context->requestId->toString();
+            return 'request:' . $requestId;
+        }
+
+        if ($context->sessionId !== null) {
+            $sessionId = is_string($context->sessionId) ? $context->sessionId : $context->sessionId->toString();
+            return 'session:' . $sessionId;
+        }
+
+        if ($context->userId !== null) {
+            return 'user:' . $context->userId;
+        }
+
+        return null;
+    }
+
+    /**
+     * Get correlation from cache
+     */
+    private function getCorrelation(CacheKey $cacheKey): ExceptionCorrelation
+    {
+        $result = $this->cache->get($cacheKey);
+        $item = $result->getFirstHit();
+
+        if ($item === null) {
+            return new ExceptionCorrelation(correlationKey: '');
+        }
+
+        $value = $item->value;
+        if (is_array($value)) {
+            return new ExceptionCorrelation(
+                correlationKey: $value['correlation_key'] ?? '',
+                exceptionIds: $value['exception_ids'] ?? [],
+                rootCauseId: $value['root_cause_id'] ?? null
+            );
+        }
+
+        return new ExceptionCorrelation(correlationKey: '');
+    }
+
+    /**
+     * Store correlation in cache
+     */
+    private function storeCorrelation(CacheKey $cacheKey, ExceptionCorrelation $correlation): void
+    {
+        $cacheItem = CacheItem::fromKey(
+            $cacheKey,
+            $correlation->toArray(),
+            Duration::fromSeconds(self::CACHE_TTL)
+        );
+
+        $this->cache->set($cacheItem);
+    }
+}
+