feat: PHP API foundation - router, config, helpers, SM-2 algorithm

edu/api/config.php

@@ -0,0 +1,30 @@
+<?php
+$db_host = getenv('EDU_DB_HOST') ?: 'postgres';
+$db_port = getenv('EDU_DB_PORT') ?: '5432';
+$db_name = getenv('EDU_DB_NAME') ?: 'edu';
+$db_user = getenv('EDU_DB_USER') ?: 'postgres';
+$db_pass = getenv('EDU_DB_PASS') ?: '';
+
+try {
+    $pdo = new PDO(
+        "pgsql:host={$db_host};port={$db_port};dbname={$db_name}",
+        $db_user, $db_pass,
+        [
+            PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION,
+            PDO::ATTR_DEFAULT_FETCH_MODE => PDO::FETCH_ASSOC,
+            PDO::ATTR_EMULATE_PREPARES => false
+        ]
+    );
+} catch (PDOException $e) {
+    http_response_code(500);
+    echo json_encode(['error' => 'Datenbankverbindung fehlgeschlagen']);
+    exit;
+}
+
+ini_set('session.cookie_httponly', 1);
+ini_set('session.cookie_secure', 1);
+ini_set('session.cookie_samesite', 'Strict');
+ini_set('session.use_strict_mode', 1);
+session_start();
+
+define('CONTENT_DIR', __DIR__ . '/../content');