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-pad-codewords.php

@@ -0,0 +1,112 @@
+<?php
+
+declare(strict_types=1);
+
+require_once __DIR__ . '/../../vendor/autoload.php';
+
+echo "=== Pad Codewords Analysis ===\n\n";
+
+// For "HELLO WORLD", Version 1, Level M:
+// - Mode: 4 bits (0100)
+// - Count: 8 bits (00001011)
+// - Data: 11 bytes = 88 bits
+// - Total so far: 100 bits
+// - Required: 128 bits (16 codewords * 8)
+// - Need: 28 more bits
+
+echo "Bit breakdown:\n";
+echo "Mode: 4 bits\n";
+echo "Count: 8 bits\n";
+echo "Data: 88 bits (11 bytes)\n";
+echo "Subtotal: 100 bits\n";
+echo "Required: 128 bits\n";
+echo "Needed: 28 bits\n\n";
+
+// Terminator: 4 bits (0000)
+$terminator = "0000";
+echo "After terminator: 104 bits\n";
+
+// Pad to multiple of 8: 104 is already multiple of 8
+echo "After padding to 8: 104 bits\n";
+
+// Need 24 more bits (3 pad codewords)
+$padBytes = ['11101100', '00010001'];
+$padSequence = $padBytes[0] . $padBytes[1] . $padBytes[0];
+echo "Pad sequence (24 bits): {$padSequence}\n\n";
+
+// So the full bit string should be:
+$fullBits = "0100" . // Mode
+            "00001011" . // Count
+            "0100100001000101010011000100110001001111001000000101011101001111010100100100110001000100" . // Data (88 bits)
+            "0000" . // Terminator
+            $padSequence; // 24 bits
+
+echo "Full bit string (128 bits):\n";
+echo $fullBits . "\n\n";
+
+// Convert to codewords
+$codewords = [];
+for ($i = 0; $i < 128; $i += 8) {
+    $byte = substr($fullBits, $i, 8);
+    $codewords[] = bindec($byte);
+}
+
+echo "Codewords from our calculation:\n";
+echo implode(', ', $codewords) . "\n\n";
+
+// Expected codewords
+$expected = [64, 180, 132, 84, 196, 196, 242, 5, 116, 245, 174, 59, 64, 109, 236, 233];
+echo "Expected codewords:\n";
+echo implode(', ', $expected) . "\n\n";
+
+// Compare bit by bit
+echo "=== Bit-by-Bit Comparison ===\n";
+for ($i = 0; $i < 16; $i++) {
+    $ourBits = str_pad(decbin($codewords[$i]), 8, '0', STR_PAD_LEFT);
+    $expectedBits = str_pad(decbin($expected[$i]), 8, '0', STR_PAD_LEFT);
+    
+    if ($ourBits !== $expectedBits) {
+        echo "❌ Codeword {$i}: {$ourBits} vs {$expectedBits}\n";
+        
+        // Show which bits differ
+        for ($j = 0; $j < 8; $j++) {
+            if ($ourBits[$j] !== $expectedBits[$j]) {
+                echo "   Bit {$j} differs: got '{$ourBits[$j]}', expected '{$expectedBits[$j]}'\n";
+            }
+        }
+    } else {
+        echo "✅ Codeword {$i}: {$ourBits}\n";
+    }
+}
+
+// Let's check what the expected codewords represent in bits
+echo "\n=== Expected Bit String ===\n";
+$expectedBitString = '';
+foreach ($expected as $codeword) {
+    $expectedBitString .= str_pad(decbin($codeword), 8, '0', STR_PAD_LEFT);
+}
+
+echo "Expected bit string (128 bits):\n";
+echo $expectedBitString . "\n\n";
+
+// Compare with our bit string
+echo "Our bit string (128 bits):\n";
+echo $fullBits . "\n\n";
+
+$differences = 0;
+for ($i = 0; $i < 128; $i++) {
+    if ($fullBits[$i] !== $expectedBitString[$i]) {
+        $differences++;
+        if ($differences <= 10) {
+            echo "Bit {$i} differs: got '{$fullBits[$i]}', expected '{$expectedBitString[$i]}'\n";
+        }
+    }
+}
+
+if ($differences === 0) {
+    echo "✅ Bit strings match!\n";
+} else {
+    echo "❌ {$differences} bits differ\n";
+}
+
+