Lehrplan: Country-Helper + Landeinstellung live

- App/php/lib/Country.php: Kaskade session → classes → teachers →
  cookie → 'AT', Helper current()/flag()/label()/allCountries()
- App/php/api/country.php: GET + POST /api/country
- country-Spalten in teachers, classes, student_sessions (idempotent)
- Native-<select>-Picker im Header aller öffentlichen Seiten
  (modul-*.php, lehrplan.php, simulationen.php)
- Footer-Links "Andere Länder: 🇨🇭 🇩🇪 🇱🇮"
- lehrplan.php liest Default-Filter jetzt aus Country::current()
- iPad-freundlich: Native Select gibt Wheel-Picker auf iOS,
  Touch-Ziel >=40px

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

App/php/seed_content_architecture.php

@@ -23,6 +23,29 @@ $db = getDB();
 
 echo "=== Content-Architektur Seed ===\n";
 
+// ------------------------------------------------------------------
+// 0. Country-Spalten (Landeinstellung-Kaskade) idempotent ergaenzen
+// ------------------------------------------------------------------
+// Auflösung: students.country? (optional) → classes → teachers → Cookie → AT
+// Schreibend nutzt nur Profil-Admin; Lese-Resolver in App/php/lib/Country.php
+$countryTargets = [
+    'teachers'         => 'country CHAR(2) NULL DEFAULT NULL AFTER email',
+    'classes'          => 'country CHAR(2) NULL DEFAULT NULL',
+    'student_sessions' => 'country CHAR(2) NULL DEFAULT NULL',
+];
+foreach ($countryTargets as $tbl => $def) {
+    try {
+        $exists = $db->query("SHOW COLUMNS FROM `$tbl` LIKE 'country'")->fetch();
+        if (!$exists) {
+            $db->exec("ALTER TABLE `$tbl` ADD COLUMN $def");
+            echo "  $tbl: Spalte country ergaenzt\n";
+        }
+    } catch (Throwable $e) {
+        echo "  $tbl: Hinweis — " . $e->getMessage() . "\n";
+    }
+}
+
+
 // ------------------------------------------------------------------
 // 1. Tabellen
 // ------------------------------------------------------------------