A user reports ~0.7 MiB/s RSS growth; the one theory offered so far
(connection leak) was debunked, so instead of guessing: measure. New
core/diagnostics/memory_tracker wraps tracemalloc behind three GET endpoints
the user can drive from a browser:
/api/debug/memory/start begin tracing + baseline snapshot (idempotent)
/api/debug/memory/report top allocation sites by GROWTH since the baseline
(?top=N), with traced totals + process RSS so we
can see how much of the real growth tracing
accounts for; 15-frame tracebacks name the caller
/api/debug/memory/stop end tracing, free trace bookkeeping
Opt-in by design — tracemalloc shadows every allocation while active, so it
never runs by default. RSS via psutil with a /proc fallback.
Tests: report-without-tracking returns a hint (not an error); a real
start->hog->report->stop roundtrip attributes a genuine 5MB allocation to the
test file (fun fact encoded in the test: 'x'*1000 constant-folds into ONE
shared string and traces as ~40KB — the hog must allocate at runtime); the
stat formatter is duck-typed and unit-tested.
