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/pages/_partials/country_footer.php

@@ -0,0 +1,38 @@
+<?php
+/**
+ * Country-Footer — „Andere Länder: 🇨🇭 / 🇩🇪 / 🇱🇮"
+ * --------------------------------------------------
+ * Kleine Zeile unten in den öffentlichen Seiten. Zeigt die jeweils
+ * *nicht* aktuell gewählten Länder mit Flaggen-Link.
+ */
+require_once __DIR__ . '/../../php/lib/Country.php';
+
+$current = Country::current();
+$others = array_filter(Country::allCountries(), fn($c) => $c !== $current);
+?>
+<div class="md-country-foot">
+  Andere Länder:
+  <?php foreach ($others as $c): ?>
+    <a href="?country=<?= htmlspecialchars($c) ?>"
+       onclick="event.preventDefault(); window.__GGS_setCountry('<?= htmlspecialchars($c) ?>');"
+       class="md-country-foot-link"
+       title="<?= htmlspecialchars(Country::label($c)) ?>">
+      <?= Country::flag($c) ?> <?= htmlspecialchars(Country::label($c)) ?>
+    </a>
+  <?php endforeach; ?>
+</div>
+
+<style>
+  .md-country-foot {
+    font-size: .78rem; color: var(--ggs-text-muted);
+    padding: .6rem 0 0;
+    text-align: center;
+  }
+  .md-country-foot a {
+    display: inline-block; margin: 0 .3rem; padding: .3rem .5rem;
+    color: var(--ggs-fjord); text-decoration: none;
+    border-radius: var(--ggs-radius-sm);
+    min-height: 32px;
+  }
+  .md-country-foot a:hover { background: var(--ggs-fjord-light); }
+</style>

App/pages/_partials/country_picker.php

@@ -0,0 +1,93 @@
+<?php
+/**
+ * Country-Picker — Native <select> im Header
+ * -------------------------------------------
+ * Wird per include in den Modul-/Lehrplan-/Simulationen-Seiten eingebunden.
+ *
+ * Erwartet im eltern-Scope:
+ *   $bp         BASE_PATH
+ *
+ * Beim Ändern:
+ *   - POST auf /php/api/country.php (Session + Cookie)
+ *   - Fallback: Cookie via JS
+ *   - Seite wird neu geladen, damit alle Server-seitigen Filter greifen
+ */
+
+require_once __DIR__ . '/../../php/lib/Country.php';
+
+if (!isset($bp)) $bp = defined('BASE_PATH') ? BASE_PATH : '';
+$currentCountry = Country::current();
+?>
+<form class="md-country-form" method="post" action="#" onsubmit="return false;" aria-label="Land auswählen">
+  <label for="md-country-select" class="md-country-label">
+    <?= Country::flag($currentCountry) ?>
+  </label>
+  <select id="md-country-select" class="md-country-select"
+          onchange="window.__GGS_setCountry(this.value)">
+    <?php foreach (Country::allCountries() as $code): ?>
+      <option value="<?= htmlspecialchars($code) ?>"
+              <?= $code === $currentCountry ? 'selected' : '' ?>>
+        <?= Country::flag($code) ?> <?= Country::label($code) ?>
+      </option>
+    <?php endforeach; ?>
+  </select>
+</form>
+
+<style>
+  /* Native-Select iPad-freundlich gestylt */
+  .md-country-form {
+    display: inline-flex; align-items: center; gap: .3rem;
+    background: var(--ggs-white); border: 1px solid var(--ggs-border);
+    border-radius: var(--ggs-radius-sm);
+    padding: 0 .5rem 0 .75rem; min-height: 40px;
+  }
+  .md-country-form:hover, .md-country-form:focus-within {
+    border-color: var(--ggs-fjord);
+  }
+  .md-country-label {
+    font-size: 1.1rem; line-height: 1; pointer-events: none;
+  }
+  .md-country-select {
+    appearance: auto;               /* native Wheel-Picker auf iOS */
+    -webkit-appearance: auto;
+    background: transparent; border: 0; cursor: pointer;
+    font-size: .85rem; font-weight: 600; font-family: inherit;
+    color: var(--ggs-fjord-dark);
+    padding: .5rem .2rem; min-height: 40px;
+  }
+  .md-country-select:focus { outline: none; }
+</style>
+
+<script>
+/*
+ * window.__GGS_setCountry(code)
+ *
+ * 1. POST an /php/api/country.php (falls verfügbar) — persistiert Session + Cookie.
+ * 2. Zusätzlich lokalen Cookie setzen (Fallback, wenn API-Call scheitert).
+ * 3. Seite reloaden, damit Server-Filter greifen (Lehrplan-Default etc.).
+ */
+if (typeof window.__GGS_setCountry !== 'function') {
+  window.__GGS_setCountry = function (code) {
+    try {
+      // Local Cookie als sofortiger Fallback (1 Jahr)
+      document.cookie = 'ggs-country=' + encodeURIComponent(code)
+        + '; Max-Age=' + (60*60*24*365)
+        + '; Path=<?= $bp ?: "/" ?>; SameSite=Lax';
+    } catch (e) {}
+    // Server-Speicherung
+    fetch('<?= $bp ?>/api/country', {
+      method: 'POST',
+      headers: { 'Content-Type': 'application/json' },
+      body: JSON.stringify({ country: code })
+    }).catch(function () {
+      // Netz weg, kein Problem — Cookie reicht als Fallback
+    }).finally(function () {
+      // Seite neu laden, damit Server-Filter (z.B. lehrplan.php ?country=...) greifen
+      // Wenn in URL bereits ?country=... steht, diesen Parameter überschreiben
+      var u = new URL(window.location.href);
+      u.searchParams.set('country', code);
+      window.location.href = u.toString();
+    });
+  };
+}
+</script>

App/pages/_partials/modul_detail.php

@@ -404,6 +404,7 @@ $countryMeta = [
   <?php if ($easyActive): ?>
     <span class="md-btn-sm md-easy-pill" title="Leichte Sprache ist aktiv">🟢 Leichte Sprache</span>
   <?php endif; ?>
+  <?php include __DIR__ . '/country_picker.php'; ?>
   <a href="<?= $bp ?>/pages/simulationen.php" class="md-btn-sm">Alle Simulationen</a>
   <a href="<?= $bp ?>/pages/lehrplan.php" class="md-btn-sm">Lehrplan</a>
   <a href="<?= $bp ?>/glossar" class="md-btn-sm">Glossar</a>
@@ -631,6 +632,7 @@ $countryMeta = [
     <a href="<?= $bp ?>/impressum.html">Impressum</a> ·
     <a href="<?= $bp ?>/datenschutz.html">Datenschutz</a>
   </div>
+  <?php include __DIR__ . '/country_footer.php'; ?>
 </footer>
 
 <script>