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.

src/Framework/ExceptionHandling/Scope/ErrorScope.php

@@ -0,0 +1,135 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\Framework\ExceptionHandling\Scope;
+
+use App\Framework\DI\Initializer;
+use Fiber;
+
+/**
+ * Error Scope Stack Manager
+ *
+ * Manages fiber-aware scope stack for error context enrichment.
+ * Each fiber has its own isolated scope stack.
+ *
+ * PHP 8.5+ with fiber isolation and automatic cleanup.
+ */
+final class ErrorScope
+{
+    /** @var array<int, array<ErrorScopeContext>> Fiber-specific scope stacks */
+    private array $stack = [];
+
+    #[Initializer]
+    public static function initialize(): self
+    {
+        return new self();
+    }
+
+    /**
+     * Enter a new error scope
+     *
+     * @param ErrorScopeContext $context Scope context to enter
+     * @return int Token for leaving this scope (stack depth)
+     */
+    public function enter(ErrorScopeContext $context): int
+    {
+        $id = $this->fiberId();
+        $this->stack[$id] ??= [];
+        $this->stack[$id][] = $context;
+
+        return count($this->stack[$id]);
+    }
+
+    /**
+     * Exit error scope(s)
+     *
+     * @param int $token Token from enter() - exits all scopes until this depth
+     */
+    public function exit(int $token = 0): void
+    {
+        $id = $this->fiberId();
+
+        if (!isset($this->stack[$id])) {
+            return;
+        }
+
+        if ($token === 0) {
+            // Exit only the most recent scope
+            array_pop($this->stack[$id]);
+        } else {
+            // Exit all scopes until token depth
+            while (!empty($this->stack[$id]) && count($this->stack[$id]) >= $token) {
+                array_pop($this->stack[$id]);
+            }
+        }
+
+        // Cleanup empty stack
+        if (empty($this->stack[$id])) {
+            unset($this->stack[$id]);
+        }
+    }
+
+    /**
+     * Get current error scope context
+     *
+     * @return ErrorScopeContext|null Current scope or null if no scope active
+     */
+    public function current(): ?ErrorScopeContext
+    {
+        $id = $this->fiberId();
+        $stack = $this->stack[$id] ?? [];
+
+        $current = end($stack);
+        return $current !== false ? $current : null;
+    }
+
+    /**
+     * Check if any scope is active
+     */
+    public function hasScope(): bool
+    {
+        $id = $this->fiberId();
+        return !empty($this->stack[$id]);
+    }
+
+    /**
+     * Get scope depth (number of nested scopes)
+     */
+    public function depth(): int
+    {
+        $id = $this->fiberId();
+        return count($this->stack[$id] ?? []);
+    }
+
+    /**
+     * Get fiber ID for isolation
+     *
+     * Returns 0 for main fiber, unique ID for each Fiber
+     */
+    private function fiberId(): int
+    {
+        $fiber = Fiber::getCurrent();
+        return $fiber ? spl_object_id($fiber) : 0;
+    }
+
+    /**
+     * Clear all scopes (for testing/cleanup)
+     */
+    public function clear(): void
+    {
+        $this->stack = [];
+    }
+
+    /**
+     * Get statistics for monitoring
+     */
+    public function getStats(): array
+    {
+        return [
+            'active_fibers' => count($this->stack),
+            'total_scopes' => array_sum(array_map('count', $this->stack)),
+            'max_depth' => !empty($this->stack) ? max(array_map('count', $this->stack)) : 0,
+        ];
+    }
+}