performance-memory-comparison-developers-need-to-detect-memory-leaks-introduced--4d01ed3d

THEN Implement a two-step diff workflow: `memory_start_diff()` takes a baseline snapshot and returns a `diff_id`; `memory_stop_diff(diff_id)` takes a final snapshot, compares it to the baseline on the server, and returns a delta summary including heap size delta, new detached DOM nodes, and per-constructor object deltas with retained size changes.

{
  "diff_id": "diff-abc-123",
  "heap_size_delta": 512345,
  "new_detached_dom_nodes": 5,
  "object_deltas": [
    { "constructor": "ModalComponent", "delta": 1, "retained_size_delta": 45678 },
    { "constructor": "(string)", "delta": 50, "retained_size_delta": 10240 }
  ]
}