* ci: right-size Blacksmith runners by workload
* ci: retain static runner capacity supported by utilization
* ci: retain observational runner for peak CPU and memory demand
* ci: restore Windows build to 16 vCPU after runtime regression
* ci: trial 4-vCPU runtime packaging to reduce CPU time allocation
* ci: trial 2-vCPU Linux packaging and serial Windows tests
* ci: include Windows packaging in 2-vCPU trial