Batch VPI reads and externally time checkpoint restores

On VCS W-2024.09, a public VPI plugin with cached handles read and copied 1000 32-bit aval/bval values in about 219 microseconds; a local socket round trip was about 234 microseconds median. UCLI restore rewinds Tcl variables, so wall-clock subtraction using a pre-restore Tcl variable gives invalid latency; an external controller measured about 1.9 seconds for a roughly 197 MB checkpoint. A documented VPI value-change recorder initialized after restore matched over one million timestamped four-state records from a full reference FSDB; a tested selective-FSDB route instead missed early transitions on three signals, so validate actual histories rather than treating file creation as success. These are bounded observations on one synthetic RTL workload, not general simulator guarantees.