The helper chat is absolutely right, and you should buy whoever (or whatever)
wrote that a coffee. That is top-tier, battle-hardened distributed systems
engineering advice.

They caught a massive race-condition trap (the snapshot/stream gap), corrected
my wraparound math for the RingBuffer, and correctly pointed out that OPFS
(Origin Private File System) is the modern, highly-performant way to save
files locally in a Web Worker.

Let's adopt their exact "Recommended order of operations."

Step 1 is implementing the Monotonic Sequence Number (seq) and the Telemetry
Heartbeat. We will expand the RingBuffer to 7 values so it can hold both a
cmdId and a seq number: [cmdId, seq, qx, qy, qz, voxelIndex, voxelData].

2. Update mesh_worker.ts
We need to track lastAppliedSeq and add a setInterval that acts as the
heartbeat to report health back to the main thread.

3. Update renderer.ts
Finally, we need to declare nextSeq and pass it into our array when clicking,
plus listen for the new telemetry heartbeat.

If you apply these changes and load the app, the engine will visually look
exactly the same, but your console will now pulse every second with the
engine's health, and every click is now cryptographically sequenced.

When you verify that works, we can move directly to Step 2: OPFS Local
Persistence!