Add JSDoc to every public export in cursorTelemetryBuffer so the module
meets the 80% docstring-coverage threshold, and make two silent-drop
paths observable:
- endSession() now returns the number of pending batches evicted by the
maxPendingBatches cap and emits console.warn when any are dropped.
- prependBatch() defensively trims and warns if an unusual retry pattern
would push the queue past the cap (normal retry after takeNextBatch()
stays a no-op).
Tests cover both drop paths.
shaun0927
adc610544c