Media browser: recursive scan entire content/ tree, /-media/ URL prefix, editor change detection fix

- handleMediaList() now scans content/ recursively for all media files
- URLs use /-media/ prefix mapping directly to content/ (no special cases)
- index.php: added /-media/ route, kept /-assets/ for backward compat
- editor-toolbar.js: fixed editor.on('change') placement (was inside switchMode)
- content-edit.php and content-new.php: back-btn unsaved-changes detection
- Removed unused __editorCleanup global

admin/templates/pages/content-move-form.php

@@ -0,0 +1,34 @@
+<h2 class="mb-4"><i class="bi bi-arrows-move"></i> <?= is_file($fullPath) ? 'Bestand' : 'Map' ?> verplaatsen</h2>
+
+<form method="post" class="card shadow-sm">
+    <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($csrf) ?>">
+
+    <div class="card-body">
+        <div class="mb-3">
+            <label class="form-label text-muted">Te verplaatsen item</label>
+            <p class="form-control-plaintext fw-bold">
+                <i class="bi <?= is_file($fullPath) ? 'bi-file' : 'bi-folder' ?>"></i>
+                <?= htmlspecialchars(basename($fullPath)) ?>
+            </p>
+        </div>
+        <div class="mb-3">
+            <label for="target_dir" class="form-label">Doelmap</label>
+            <select class="form-select" id="target_dir" name="target_dir" required>
+                <option value="">-- Selecteer doelmap --</option>
+                <option value="">/ (hoofdmap)</option>
+                <?php foreach ($dirs as $d): ?>
+                    <option value="<?= htmlspecialchars($d) ?>"><?= htmlspecialchars($d) ?></option>
+                <?php endforeach; ?>
+            </select>
+            <div class="form-text">Selecteer de map waar het item naartoe verplaatst moet worden.</div>
+        </div>
+        <?php if (!empty($message)): ?>
+            <div class="alert alert-<?= $messageType ?>"><?= htmlspecialchars($message) ?></div>
+        <?php endif; ?>
+    </div>
+
+    <div class="card-footer text-end">
+        <a href="admin.php?route=content&dir=<?= urlencode(dirname($item) === '.' ? '' : dirname($item)) ?>" class="btn btn-secondary">Annuleren</a>
+        <button type="submit" class="btn btn-primary"><i class="bi bi-check-lg"></i> Verplaatsen</button>
+    </div>
+</form>