PWA: install button, one icon badge for Signal, mail and tasks due, share target for files, manifest launch handler

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

public/share.js

@@ -0,0 +1,17 @@
+'use strict';
+// Files shared into NE Hub from other apps (the manifest's share target; sw.js keeps them): choose a Seafile folder, then upload.
+async function shareCheck() {
+  if (!('caches' in window)) return;
+  let c, keys;
+  try { c = await caches.open('hub-share'); keys = await c.keys(); } catch { return; }
+  if (!keys.length) return;
+  const clear = async () => { for (const k of await c.keys()) await c.delete(k); };
+  if (!allowed('files')) { await clear(); toast('You do not have the Files tab, so shared files were discarded'); return; }
+  const files = [];
+  for (const k of keys) { const r = await c.match(k); if (r) files.push(new File([await r.blob()], decodeURIComponent(r.headers.get('x-name') || 'file'), { type: r.headers.get('content-type') || '' })); }
+  const loc = store.get('office_loc');
+  const dst = await chooseFolder('Save ' + (files.length === 1 ? '“' + files[0].name + '”' : files.length + ' shared files') + ' to…', loc ? { repo: loc.repo, repoName: loc.repoName || '', dir: loc.dir } : null, { okLabel: 'Upload here', newFolder: true });
+  await clear();
+  if (!dst) return toast('Shared files discarded');
+  enqueueUploads(dst.repo, dst.dir, files.map(file => ({ file })));
+}