drop zone, and remove beta tag from mraid checker

src/tools/plecUpload.ts

@@ -392,11 +392,14 @@ ${getToolWebviewStyles()}
   document.getElementById('upload').addEventListener('click', () => {
     clearErrors();
     statusEl.textContent = '';
+    statusEl.classList.remove('is-busy');
     setPreview('');
     if (rows.length === 0) {
       statusEl.innerHTML = '<span class="err">Select at least one file.</span>';
       return;
     }
+    statusEl.textContent = 'Uploading...';
+    statusEl.classList.add('is-busy');
     vscode.postMessage({ type: 'upload', rows });
   });
   openResultBtn.addEventListener('click', () => {
@@ -417,19 +420,22 @@ ${getToolWebviewStyles()}
       addFiles(m.files || []);
     } else if (m.type === 'status') {
       statusEl.textContent = m.message;
-      statusEl.className = 'status-panel';
+      statusEl.className = 'status-panel is-busy';
     } else if (m.type === 'error') {
+      statusEl.classList.remove('is-busy');
       statusEl.innerHTML = '';
       const div = document.createElement('div');
       div.className = 'err';
       div.textContent = m.message;
       statusEl.appendChild(div);
     } else if (m.type === 'rowError') {
+      statusEl.classList.remove('is-busy');
       const row = rows.find(r => r.id === m.rowId);
       if (row) row.error = m.message;
       renderRows();
       statusEl.innerHTML = '<span class="err">Fix row errors and retry.</span>';
     } else if (m.type === 'result') {
+      statusEl.classList.remove('is-busy');
       statusEl.innerHTML = '<span class="ok">Upload complete.</span>';
       setPreview(m.preview);
     }