feat(admin): external media import modal + thumbnail fixes for reference events\n\n- Photos tab: replace inline external folder picker with a modal opened via "Import from External Folder" button next to "Upload Photos"; add info that all pictures in the selected folder will be imported.\n- Admin thumbnails: align list endpoint to /api/admin/photos/:eventId/photos and always return thumbnail_url to trigger on-demand generation; normalize external paths to avoid duplicated folder segments (e.g., individual/individual) that broke resolver; improve thumbnail logging.\n- Use authenticated image fetching on admin feedback pages to prevent 401s in automation.\n- i18n: add backup.external.warning strings; complete German backup/restore coverage; add common keys (notSet, of, up, select, selected).\n- Docs: add Local (npm) setup for EXTERNAL_MEDIA_ROOT in deployment guide.\n\nRefs #17 – gallery feature request: https://github.com/the-luap/picpeak/issues/17

backend/src/services/externalMediaService.js

@@ -0,0 +1,67 @@
+const fs = require('fs').promises;
+const path = require('path');
+const { safePathJoin } = require('../utils/fileSecurityUtils');
+
+function getExternalMediaRoot() {
+  return process.env.EXTERNAL_MEDIA_ROOT || '/external-media';
+}
+
+function isUnderRoot(p) {
+  const root = path.resolve(getExternalMediaRoot());
+  const resolved = path.resolve(p);
+  return resolved === root || resolved.startsWith(root + path.sep);
+}
+
+async function list(relativePath = '') {
+  const root = getExternalMediaRoot();
+  // Normalize and ensure safe join under root
+  const targetDir = safePathJoin(root, relativePath || '.');
+
+  const entries = [];
+  try {
+    const dirents = await fs.readdir(targetDir, { withFileTypes: true });
+    for (const d of dirents) {
+      // Skip hidden files and directories
+      if (d.name.startsWith('.')) continue;
+      const full = path.join(targetDir, d.name);
+      const stat = await fs.stat(full).catch(() => null);
+      if (!stat) continue;
+
+      if (d.isDirectory()) {
+        entries.push({ name: d.name, type: 'dir' });
+      } else if (d.isFile()) {
+        const ext = path.extname(d.name).toLowerCase();
+        if (['.jpg', '.jpeg', '.png', '.webp'].includes(ext)) {
+          entries.push({ name: d.name, type: 'file', size: stat.size, mtime: stat.mtime });
+        }
+      }
+    }
+  } catch (e) {
+    // Propagate errors for caller to handle (e.g., invalid path)
+    throw e;
+  }
+
+  const rootResolved = path.resolve(root);
+  const currentResolved = path.resolve(targetDir);
+  const canNavigateUp = currentResolved !== rootResolved;
+
+  // Return normalized relative path from root
+  const relFromRoot = path.relative(rootResolved, currentResolved);
+
+  return { path: relFromRoot, entries, canNavigateUp };
+}
+
+function resolveExternalPath(event, relpath) {
+  const root = getExternalMediaRoot();
+  const base = event?.external_path ? path.join(event.external_path) : '';
+  const combined = base ? path.join(base, relpath || '') : (relpath || '');
+  return safePathJoin(root, combined);
+}
+
+module.exports = {
+  getExternalMediaRoot,
+  isUnderRoot,
+  list,
+  resolveExternalPath,
+};
+