refactor(deployment): Remove WireGuard VPN dependency and restore public service access

Remove WireGuard integration from production deployment to simplify infrastructure:
- Remove docker-compose-direct-access.yml (VPN-bound services)
- Remove VPN-only middlewares from Grafana, Prometheus, Portainer
- Remove WireGuard middleware definitions from Traefik
- Remove WireGuard IPs (10.8.0.0/24) from Traefik forwarded headers

All monitoring services now publicly accessible via subdomains:
- grafana.michaelschiemer.de (with Grafana native auth)
- prometheus.michaelschiemer.de (with Basic Auth)
- portainer.michaelschiemer.de (with Portainer native auth)

All services use Let's Encrypt SSL certificates via Traefik.

tests/debug/test-rs-reference-data-ec.php

@@ -0,0 +1,98 @@
+<?php
+
+declare(strict_types=1);
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+use App\Framework\QrCode\ErrorCorrection\ReedSolomonEncoder;
+
+echo "=== RS with Reference Data Codewords ===\n\n";
+
+// Reference data codewords from QR code specification
+$referenceData = [64, 180, 132, 84, 196, 196, 242, 5, 116, 245, 174, 59, 64, 109, 236, 233];
+$ecCodewords = 10;
+
+echo "Reference data codewords:\n";
+echo implode(', ', $referenceData) . "\n\n";
+
+$rs = new ReedSolomonEncoder();
+$ec = $rs->encode($referenceData, $ecCodewords);
+
+echo "Generated EC codewords:\n";
+echo implode(', ', $ec) . "\n\n";
+
+// Known reference EC codewords from QR code specification
+// These should be the correct EC codewords for the reference data
+$referenceEC = [0, 245, 228, 127, 21, 207, 194, 102, 66, 52];
+
+echo "Expected EC codewords (from spec):\n";
+echo implode(', ', $referenceEC) . "\n\n";
+
+// Compare
+$matches = 0;
+for ($i = 0; $i < min(count($ec), count($referenceEC)); $i++) {
+    if ($ec[$i] === $referenceEC[$i]) {
+        $matches++;
+    } else {
+        echo "❌ EC codeword {$i}: got {$ec[$i]}, expected {$referenceEC[$i]}\n";
+    }
+}
+
+if ($matches === count($referenceEC)) {
+    echo "✅ All EC codewords match reference!\n";
+} else {
+    echo "❌ {$matches}/" . count($referenceEC) . " EC codewords match\n";
+}
+
+// Verify with decoder
+require_once __DIR__ . '/test-reed-solomon-decoder.php';
+$decoder = new SimpleRSDecoder();
+
+$fullCodeword = array_merge($referenceData, $ec);
+$syndromes = $decoder->calculateSyndromes($fullCodeword, 10);
+
+echo "\nSyndromes (should all be 0):\n";
+echo implode(', ', $syndromes) . "\n";
+
+$allZero = true;
+foreach ($syndromes as $s) {
+    if ($s !== 0) {
+        $allZero = false;
+        break;
+    }
+}
+
+if ($allZero) {
+    echo "\n✅ All syndromes are zero - Reed-Solomon is CORRECT!\n";
+} else {
+    echo "\n❌ Syndromes are not all zero - Reed-Solomon is WRONG!\n";
+    echo "\nThis confirms the Reed-Solomon implementation has a bug.\n";
+}
+
+// Also test with reference EC codewords
+echo "\n=== Testing with Reference EC Codewords ===\n";
+$fullWithReferenceEC = array_merge($referenceData, $referenceEC);
+$syndromesRef = $decoder->calculateSyndromes($fullWithReferenceEC, 10);
+
+echo "Syndromes with reference EC codewords:\n";
+echo implode(', ', $syndromesRef) . "\n";
+
+$allZeroRef = true;
+foreach ($syndromesRef as $s) {
+    if ($s !== 0) {
+        $allZeroRef = false;
+        break;
+    }
+}
+
+if ($allZeroRef) {
+    echo "\n✅ Reference EC codewords are valid!\n";
+    echo "This means the reference EC codewords are correct.\n";
+    echo "Our implementation produces different (incorrect) EC codewords.\n";
+} else {
+    echo "\n❌ Even reference EC codewords are invalid!\n";
+    echo "This means either:\n";
+    echo "  1. The reference EC codewords are wrong\n";
+    echo "  2. Our syndrome calculation is wrong\n";
+}
+