feat: Add folder upload and enhance dropzone UI on invite page

Co-authored-by: aider (gemini/gemini-2.5-pro) <aider@aider.chat>

frontend/invite.html

@@ -58,14 +58,29 @@
       <div id="dropHint" class="mx-auto -mt-6 h-12 w-12 opacity-70 hidden md:block">
         <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="currentColor"><path d="M12 16V8m0 0l-3 3m3-3 3 3M4 16a4 4 0 0 0 4 4h8a4 4 0 0 0 4-4v-1a1 1 0 1 0-2 0v1a2 2 0 0 1-2 2H8a2 2 0 0 1-2-2v-1a1 1 0 1 0-2 0v1z"/></svg>
       </div>
-      <p class="mt-3 font-medium hidden md:block">Drop files here</p>
+      <p class="mt-3 font-medium hidden md:block">Drop multiple files or folders here</p>
-      <p class="mb-2 text-sm text-gray-600 dark:text-gray-400 hidden md:block">...or</p>
+      <p class="mb-5 text-sm text-gray-600 dark:text-gray-400 hidden md:block">...or</p>
-      <div class="mt-3 relative inline-block">
+      <!-- Mobile-safe choose controls -->
-        <label class="rounded-2xl bg-black text-white dark:bg-white dark:text-black px-5 py-3 hover:opacity-90 cursor-pointer select-none" aria-label="Choose files">
+      <div class="flex flex-col sm:flex-row items-center justify-center gap-y-4 sm:gap-y-0 sm:gap-x-4">
+        <div class="relative inline-block">
+          <label class="rounded-2xl bg-black text-white dark:bg-white dark:text-black px-5 py-3 hover:opacity-90 cursor-pointer select-none transition-colors" aria-label="Choose files">
             Choose files
-          <input id="fileInput" type="file" multiple class="absolute inset-0 opacity-0 cursor-pointer" />
+            <input id="fileInput"
+                   type="file"
+                   multiple
+                   class="absolute inset-0 opacity-0 cursor-pointer" />
           </label>
         </div>
+        <div class="relative inline-block">
+          <label class="rounded-2xl bg-black text-white dark:bg-white dark:text-black px-5 py-3 hover:opacity-90 cursor-pointer select-none transition-colors" aria-label="Choose a folder">
+            Choose a folder
+            <input id="folderInput"
+                   type="file"
+                   webkitdirectory
+                   class="absolute inset-0 opacity-0 cursor-pointer" />
+          </label>
+        </div>
+      </div>
       <div class="mt-4 text-sm text-gray-500 dark:text-gray-400">
         Files will be uploaded to the selected album for this invite.
       </div>
@@ -116,6 +131,7 @@
       document.getElementById('liStatus').textContent = j.active ? 'Active' : ('Inactive' + (j.inactiveReason ? (' ('+j.inactiveReason+')') : ''));
       const dz = document.getElementById('dropzone');
       const fi = document.getElementById('fileInput');
+      const foi = document.getElementById('folderInput');
       const itemsEl = document.getElementById('items');
       const pwGate = document.getElementById('pwGate');
       if (j.passwordRequired && !j.authorized) {
@@ -123,6 +139,7 @@
         pwGate.classList.remove('hidden');
         dz.classList.add('opacity-50');
         if (fi) fi.disabled = true;
+        if (foi) foi.disabled = true;
         itemsEl.innerHTML = '<div class="text-sm text-gray-500">Enter the password above to enable uploads.</div>';
         // Wire unlock button
         const pwInput = document.getElementById('pwInput');
@@ -139,6 +156,7 @@
             pwGate.classList.add('hidden');
             dz.classList.remove('opacity-50');
             if (fi) fi.disabled = false;
+            if (foi) foi.disabled = false;
             itemsEl.innerHTML = '';
             try { showBanner('Password accepted. You can upload now.', 'ok'); } catch {}
           } catch (e) {
@@ -153,6 +171,7 @@
         // Disable dropzone
         dz.classList.add('opacity-50');
         fi.disabled = true;
+        if (foi) foi.disabled = true;
         itemsEl.innerHTML = `<div class="text-sm text-gray-500">This link is not active${j.inactiveReason?` (${j.inactiveReason})`:''}.</div>`;
       }
     } catch {}