Fix BLE upload: write-with-response on CMD+DATA, on-demand advertising, wake-play-random, remove startup blink

app/app.js

@@ -38,7 +38,7 @@ function fmtBytes(n) {
 
 // ---- connection state ----
 dev.addEventListener('log', (e) => log(e.detail));
-dev.addEventListener('connected', (e) => { setConnected(true, e.detail.name); refresh(); fetchVolume(); });
+dev.addEventListener('connected', async (e) => { setConnected(true, e.detail.name); await refresh(); fetchVolume(); });
 dev.addEventListener('disconnected', () => {
   setConnected(false); deviceTracks = null; renderSlots();
   $('volume-val').textContent = '—';

app/ble.js

@@ -186,7 +186,7 @@ export class BabyMobile extends EventTarget {
 
   async _writeCmd(bytes) {
     this._requireConnected();
-    await this.cmd.writeValueWithoutResponse(Uint8Array.from(bytes));
+    await this.cmd.writeValue(Uint8Array.from(bytes));
   }
 
   async play(track) {
@@ -282,21 +282,21 @@ export class BabyMobile extends EventTarget {
       this._log(`Starting upload of ${total} bytes to slot ${track}…`);
       await this._writeCmd([CMD_UPLOAD_START, track & 0xff]);
 
-      // Send all data chunks sequentially.  Chrome on Windows (WinRT BLE) only
-      // allows one writeValueWithoutResponse in flight at a time; concurrent calls
-      // fail with "GATT operation already in progress".  Sequential writes are
-      // reliable and throughput is governed by the BLE connection interval, not
-      // by how many calls are in flight.
+      // Send all data chunks using write-with-response.  Each writeValue() call
+      // blocks until the SoftDevice sends an ATT Write Response, which only happens
+      // after it has delivered the packet to the firmware's write callback.  This
+      // provides natural per-packet flow control: CMD_UPLOAD_END cannot be sent until
+      // every data packet has been confirmed received, eliminating all OS TX-queue
+      // race conditions without any byte-counting hacks.
       for (let off = 0; off < total; off += DATA_CHUNK) {
-        await this.data.writeValueWithoutResponse(
+        await this.data.writeValue(
           wavBytes.subarray(off, Math.min(off + DATA_CHUNK, total)));
         // Cap the optimistic local count at 99%; the final 1% is filled only when
         // the device's finalize ack confirms the bytes actually landed in flash.
         report(Math.min(off + DATA_CHUNK, Math.floor(total * 0.99)));
       }
 
-      // Tell the firmware we're done. It will drain its ring buffer, write the
-      // track table, then send ONE finalize notification with the total byte count.
+      // All data confirmed received — finalize.
       await this._writeCmd([CMD_UPLOAD_END]);
 
       // Wait for that single finalize notification.  Allow up to 60 s: at 300 ms/sector

app/styles.css

@@ -87,15 +87,15 @@ label { display: inline-flex; align-items: center; gap: 8px; font-size: .9rem; c
 .handle:focus { outline: none; }
 .handle:focus .line, .handle.dragging .line { background: var(--accent); box-shadow: 0 0 6px var(--accent); }
 .handle:focus .chev, .handle.dragging .chev { filter: drop-shadow(0 0 4px var(--accent)); }
-.trim-readout { display: flex; align-items: center; gap: 12px; font-size: .85rem; color: var(--muted); }
-.time-fields { display: inline-flex; align-items: center; gap: 6px; }
+.trim-readout { display: flex; align-items: center; flex-wrap: wrap; gap: 8px 12px; font-size: .85rem; color: var(--muted); }
+.time-fields { display: inline-flex; align-items: center; gap: 6px; flex-shrink: 0; }
 .time-fields .dash { color: var(--muted); }
 .time-in {
-  width: 4.2rem; padding: 5px 7px; font-size: .85rem;
+  width: 3.8rem; min-width: 0; padding: 5px 7px; font-size: .85rem;
   background: #1c123e; color: var(--text); border: 1px solid var(--line); border-radius: 7px;
 }
-.trim-readout .clip { color: var(--accent); font-weight: 600; }
-.trim-readout button { margin-left: auto; }
+.trim-readout .clip { margin-left: auto; color: var(--accent); font-weight: 600; }
+.trim-readout button { flex-shrink: 0; }
 .level { display: flex; align-items: center; gap: 10px; width: 100%; margin-top: 12px; font-size: .85rem; color: var(--muted); }
 .level input[type=range] { flex: 1; min-width: 0; }
 .level .unit { min-width: 3.2rem; text-align: right; color: var(--accent); font-weight: 600; }

app/sw.js

@@ -1,5 +1,5 @@
 // sw.js — minimal offline cache so the PWA launches without a network.
-const CACHE = 'babymobile-v8';
+const CACHE = 'babymobile-v9';
 const ASSETS = [
   './', './index.html', './styles.css',
   './app.js', './ble.js', './wav.js',