Preserve onboard preview recordings across backpressure and share the complete spatial scene

apps/control-station/test/k1PreviewFrames.test.mjs

@@ -78,3 +78,16 @@ test('onboard camera admits immediate sourceopen and ignores callbacks after clo
   assert.equal(ready,1);assert.equal(failed,0);
  }finally{globalThis.MediaSource=saved.media;URL.createObjectURL=saved.create;URL.revokeObjectURL=saved.revoke;}
 });
+
+test('a recovered media peer resumes a recording without reinserting old RRD batches',async()=>{
+ const {previewRecording}=await server.ssrLoadModule('@xgrids-k1/frontend/sensors/previewFrames.ts');
+ const sent=[];const cursor=previewRecording(value=>sent.push(value));
+ const payload=new Uint8Array(12);payload.set([82,82,70,50]);
+ assert.equal(cursor.accept(1,payload),true);
+ // The ACK was lost, so the new peer resends the exact complete batch.
+ assert.equal(cursor.accept(1,payload),false);
+ assert.equal(cursor.after,1);
+ assert.throws(()=>cursor.accept(3,payload),/cursor gap/);
+ assert.equal(cursor.accept(2,payload),true);
+ assert.equal(sent.length,2);
+});