Podcast: resume where you left off, synced between devices (shared progress store with audiobooks)

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

progress.js

@@ -0,0 +1,15 @@
+// Where each person has got to in each thing they listen to (audiobooks, podcast episodes), kept on the server so every device agrees.
+// One file per person; for each item the newest report wins, so an old device cannot overwrite a newer position.
+const fs = require('fs'), path = require('path');
+const users = require('./users');
+
+module.exports = name => {
+  const file = () => path.join(users.dir(), name);
+  const load = () => { try { return JSON.parse(fs.readFileSync(file(), 'utf8')); } catch { return {}; } };
+  const merge = body => {
+    const mine = load();
+    for (const [k, v] of Object.entries(body || {})) if (/^[\w.:-]{1,80}$/.test(k) && v && typeof v === 'object' && (v.t || 0) >= ((mine[k] || {}).t || 0)) mine[k] = { pos: +v.pos || 0, dur: +v.dur || 0, t: +v.t || 0 };
+    const f = file(), tmp = f + '.tmp'; fs.writeFileSync(tmp, JSON.stringify(mine), { mode: 0o600 }); fs.renameSync(tmp, f); return mine;
+  };
+  return { load, merge };
+};