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/Metrics/PrometheusExporter.php

@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\ExceptionHandling\Metrics;
+
+/**
+ * Prometheus Exporter
+ *
+ * Exports exception metrics in Prometheus format.
+ */
+final readonly class PrometheusExporter
+{
+    /**
+     * Export metrics in Prometheus format
+     *
+     * @param ExceptionMetrics $metrics Metrics to export
+     * @return string Prometheus-formatted metrics
+     */
+    public function export(ExceptionMetrics $metrics): string
+    {
+        $lines = [];
+
+        // Total exception count
+        $lines[] = sprintf(
+            'exception_total %d',
+            $metrics->totalCount
+        );
+
+        // Exceptions by class
+        foreach ($metrics->byClass as $class => $count) {
+            $sanitizedClass = $this->sanitizeMetricName($class);
+            $lines[] = sprintf(
+                'exception_by_class{exception_class="%s"} %d',
+                $sanitizedClass,
+                $count
+            );
+        }
+
+        // Exceptions by component
+        foreach ($metrics->byComponent as $component => $count) {
+            $sanitizedComponent = $this->sanitizeMetricName($component);
+            $lines[] = sprintf(
+                'exception_by_component{component="%s"} %d',
+                $sanitizedComponent,
+                $count
+            );
+        }
+
+        // Average execution time
+        $lines[] = sprintf(
+            'exception_average_execution_time_ms %.2f',
+            $metrics->averageExecutionTimeMs
+        );
+
+        return implode("\n", $lines);
+    }
+
+    /**
+     * Sanitize metric name for Prometheus
+     */
+    private function sanitizeMetricName(string $name): string
+    {
+        // Replace invalid characters
+        $sanitized = preg_replace('/[^a-zA-Z0-9_:]/', '_', $name);
+        return $sanitized;
+    }
+}
+