feat(cms): add per-page external URL override — backend

backend/src/database/db.js

@@ -464,15 +464,31 @@ async function ensureGlobalCategories() {
       table.text('content_en');
       table.text('content_de');
       table.string('logo_url').nullable();
+      table.boolean('use_external_url').notNullable().defaultTo(false);
+      table.string('external_url').nullable();
       table.timestamp('updated_at').defaultTo(db.fn.now());
     });
-  } else if (!(await db.schema.hasColumn('cms_pages', 'logo_url'))) {
+  } else {
+    if (!(await db.schema.hasColumn('cms_pages', 'logo_url'))) {
       // Online migration for existing deployments — see issue #324, per-page
       // logo override for admin-customisable error pages.
       await db.schema.alterTable('cms_pages', (table) => {
         table.string('logo_url').nullable();
       });
     }
+    if (!(await db.schema.hasColumn('cms_pages', 'use_external_url'))) {
+      // Per-page toggle to redirect visitors to an external imprint /
+      // privacy-policy URL instead of rendering the internal CMS content.
+      await db.schema.alterTable('cms_pages', (table) => {
+        table.boolean('use_external_url').notNullable().defaultTo(false);
+      });
+    }
+    if (!(await db.schema.hasColumn('cms_pages', 'external_url'))) {
+      await db.schema.alterTable('cms_pages', (table) => {
+        table.string('external_url').nullable();
+      });
+    }
+  }
 
   const categoryCountRow = await db('photo_categories').count({ count: 'id' }).first();
   const categoryCount = categoryCountRow ? Number(categoryCountRow.count) : 0;

backend/src/routes/adminCMS.js

@@ -71,7 +71,9 @@ router.put('/pages/:slug', adminAuth, requirePermission('cms.edit'), [
   body('title_de').optional().isString(),
   body('content_en').optional().isString(),
   body('content_de').optional().isString(),
-  body('logo_url').optional({ nullable: true }).isString()
+  body('logo_url').optional({ nullable: true }).isString(),
+  body('use_external_url').optional().isBoolean(),
+  body('external_url').optional({ nullable: true }).isString()
 ], async (req, res) => {
   try {
     const errors = validationResult(req);
@@ -80,7 +82,26 @@ router.put('/pages/:slug', adminAuth, requirePermission('cms.edit'), [
     }
 
     const { slug } = req.params;
-    const { title_en, title_de, content_en, content_de, logo_url } = req.body;
+    const { title_en, title_de, content_en, content_de, logo_url, use_external_url, external_url } = req.body;
+
+    // When the external-URL toggle is on, the URL must parse and use https://.
+    // express-validator's isURL() is too permissive (allows http:, ftp:, etc.) —
+    // an explicit protocol check is the security-relevant gate.
+    if (use_external_url === true) {
+      const candidate = typeof external_url === 'string' ? external_url.trim() : '';
+      if (!candidate) {
+        return res.status(400).json({ error: 'external_url is required when use_external_url is true' });
+      }
+      let parsed;
+      try {
+        parsed = new URL(candidate);
+      } catch (_err) {
+        return res.status(400).json({ error: 'external_url must be a valid URL' });
+      }
+      if (parsed.protocol !== 'https:') {
+        return res.status(400).json({ error: 'external_url must use https://' });
+      }
+    }
 
     const page = await db('cms_pages').where('slug', slug).first();
     if (!page) {
@@ -99,6 +120,13 @@ router.put('/pages/:slug', adminAuth, requirePermission('cms.edit'), [
     if (Object.prototype.hasOwnProperty.call(req.body, 'logo_url')) {
       updateFields.logo_url = logo_url || null;
     }
+    if (Object.prototype.hasOwnProperty.call(req.body, 'use_external_url')) {
+      updateFields.use_external_url = !!use_external_url;
+    }
+    if (Object.prototype.hasOwnProperty.call(req.body, 'external_url')) {
+      const trimmed = typeof external_url === 'string' ? external_url.trim() : '';
+      updateFields.external_url = trimmed || null;
+    }
 
     await db('cms_pages').where('slug', slug).update(updateFields);
 

backend/src/routes/publicCMS.js

@@ -25,6 +25,11 @@ router.get('/pages/:slug', async (req, res) => {
       // Per-page logo override (#324). Null means "fall back to global
       // branding logo" — the consumer decides.
       logo_url: page.logo_url || null,
+      // Per-page external-URL override. When use_external_url is true and
+      // external_url is set, consumers should redirect / link out instead
+      // of rendering the internal title/content.
+      use_external_url: !!page.use_external_url,
+      external_url: page.external_url || null,
       updated_at: page.updated_at
     });
   } catch (error) {