Resource statistics

Stackie exposes the timestamped CPU, memory, swap, I/O, and process observations supplied by each selected workload runtime. Unsupported measurements remain absent instead of being reported as zero; in particular, network and writable-layer fields are omitted until their owning runtime supplies them. List filters combine exact IDs, sandbox IDs, and labels with logical AND. Streaming calls return one complete bounded snapshot without duplicates and then close normally.