E-Mail-Retry, Voucher-Resend, Tageslimit, Docker-Politur

- Mailer::send mit Retry (2 Versuche); SMTP-Test & Templates waren bereits da
- admin/vouchers.php: Code per E-Mail (erneut) versenden (ajax_resend)
- Tageslimit Voucher pro Nicht-Admin-Benutzer (Setting + Durchsetzung in index)
- Docker: HEALTHCHECK (health.php) + curl; GHCR-Publish-Workflow
- Setting user_daily_voucher_limit + enforce in integrations.php

tests/MigrationSplitterTest.php

@@ -0,0 +1,42 @@
+<?php
+namespace Tests;
+
+use PHPUnit\Framework\TestCase;
+
+require_once __DIR__ . '/../updater/MigrationRunner.php';
+
+final class MigrationSplitterTest extends TestCase
+{
+    private function split(string $sql): array
+    {
+        $rc = new \ReflectionClass(\Updater\MigrationRunner::class);
+        $inst = $rc->newInstanceWithoutConstructor();
+        $m = $rc->getMethod('splitStatements');
+        $m->setAccessible(true);
+        $parts = $m->invoke($inst, $sql);
+        return array_values(array_filter(array_map('trim', $parts), fn($s) => $s !== ''));
+    }
+
+    public function testIgnoresSemicolonsInStringsAndComments(): void
+    {
+        $sql = "INSERT INTO t (a) VALUES (\";semi;colon\"); -- comment; not split\n"
+             . "CREATE TABLE x (id INT); /* block ; comment */ INSERT INTO y VALUES (1);";
+        $parts = $this->split($sql);
+        $this->assertCount(3, $parts);
+    }
+
+    public function testSingleStatement(): void
+    {
+        $parts = $this->split("ALTER TABLE users ADD COLUMN foo INT");
+        $this->assertCount(1, $parts);
+    }
+
+    public function testIgnorableErrorDetection(): void
+    {
+        $rc = new \ReflectionClass(\Updater\MigrationRunner::class);
+        $inst = $rc->newInstanceWithoutConstructor();
+        $this->assertTrue($inst->isIgnorableSqlError('Duplicate column name "x"', 'mysql'));
+        $this->assertTrue($inst->isIgnorableSqlError('Table already exists', 'mysql'));
+        $this->assertFalse($inst->isIgnorableSqlError('Syntax error near FROM', 'mysql'));
+    }
+}