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-padding-sequence.php

@@ -0,0 +1,110 @@
+<?php
+
+declare(strict_types=1);
+
+echo "=== Padding Sequence Analysis ===\n\n";
+
+$testData = 'HELLO WORLD';
+
+// Build bit string
+$bits = '';
+
+// 1. Mode indicator (4 bits)
+$bits .= '0100';
+
+// 2. Character count (8 bits)
+$bits .= str_pad(decbin(11), 8, '0', STR_PAD_LEFT);
+
+// 3. Data bytes
+for ($i = 0; $i < 11; $i++) {
+    $byte = ord($testData[$i]);
+    $bits .= str_pad(decbin($byte), 8, '0', STR_PAD_LEFT);
+}
+
+echo "After mode + count + data: " . strlen($bits) . " bits\n";
+
+// 4. Terminator
+$requiredBits = 16 * 8; // 128 bits
+$terminatorLength = min(4, max(0, $requiredBits - strlen($bits)));
+$bits .= str_repeat('0', $terminatorLength);
+echo "After terminator: " . strlen($bits) . " bits\n";
+
+// 5. Pad to multiple of 8
+$remainder = strlen($bits) % 8;
+if ($remainder !== 0) {
+    $bits .= str_repeat('0', 8 - $remainder);
+}
+echo "After padding to byte: " . strlen($bits) . " bits\n";
+echo "Padding bits added: " . (8 - $remainder) . "\n\n";
+
+// 6. Add pad codewords
+$padBytes = ['11101100', '00010001'];
+$padIndex = 0;
+$padSequence = '';
+while (strlen($bits) < $requiredBits) {
+    $padByte = $padBytes[$padIndex % 2];
+    $padSequence .= $padByte . ' ';
+    $bits .= $padByte;
+    $padIndex++;
+}
+
+echo "Pad codewords needed: " . (($requiredBits - strlen($bits) + strlen($padSequence)) / 8) . "\n";
+echo "Pad sequence: {$padSequence}\n\n";
+
+// Convert to codewords
+$codewords = [];
+for ($i = 0; $i < strlen($bits); $i += 8) {
+    $byte = substr($bits, $i, 8);
+    $codewords[] = bindec($byte);
+}
+
+// Expected codewords
+$expected = [64, 180, 132, 84, 196, 196, 242, 5, 116, 245, 174, 59, 64, 109, 236, 233];
+
+echo "=== Codeword Comparison ===\n";
+for ($i = 0; $i < min(count($codewords), count($expected)); $i++) {
+    $match = $codewords[$i] === $expected[$i] ? '✅' : '❌';
+    $ourBits = str_pad(decbin($codewords[$i]), 8, '0', STR_PAD_LEFT);
+    $expBits = str_pad(decbin($expected[$i]), 8, '0', STR_PAD_LEFT);
+    echo "Codeword {$i}: ours={$codewords[$i]} ({$ourBits}) exp={$expected[$i]} ({$expBits}) {$match}\n";
+    
+    if ($codewords[$i] !== $expected[$i] && $i >= 9) {
+        // Show bit context
+        $offset = $i * 8;
+        echo "  Context (bits " . ($offset - 8) . "-" . ($offset + 15) . "):\n";
+        echo "    Our:      " . substr($bits, max(0, $offset - 8), 24) . "\n";
+        $expectedBits = '';
+        foreach ($expected as $cw) {
+            $expectedBits .= str_pad(decbin($cw), 8, '0', STR_PAD_LEFT);
+        }
+        echo "    Expected: " . substr($expectedBits, max(0, $offset - 8), 24) . "\n";
+    }
+}
+
+// Show what the expected padding should be
+echo "\n=== Expected Padding Analysis ===\n";
+$expectedBits = '';
+foreach ($expected as $cw) {
+    $expectedBits .= str_pad(decbin($cw), 8, '0', STR_PAD_LEFT);
+}
+
+// Find where our data ends
+$dataEnd = 4 + 8 + (11 * 8); // mode + count + data
+echo "Data ends at bit: {$dataEnd}\n";
+echo "Expected bits 0-{$dataEnd}: " . substr($expectedBits, 0, $dataEnd) . "\n";
+echo "Our bits 0-{$dataEnd}:      " . substr($bits, 0, $dataEnd) . "\n";
+
+$expectedPadding = substr($expectedBits, $dataEnd);
+$ourPadding = substr($bits, $dataEnd);
+
+echo "\nExpected padding: {$expectedPadding}\n";
+echo "Our padding:      {$ourPadding}\n";
+
+if ($expectedPadding === $ourPadding) {
+    echo "\n✅ Padding matches!\n";
+} else {
+    echo "\n❌ Padding doesn't match!\n";
+    echo "First difference at bit " . ($dataEnd + strspn($expectedPadding ^ $ourPadding, "\0")) . "\n";
+}
+
+