Motivated by a make.tcl project deploy failure ("could not delete target
binary") where the locker turned out to be 7-Zip inspecting the exe -
identifying it took several dead ends because Windows has no cheap
file-to-process reverse lookup (name matching and Process.Modules scans
both miss plain file handles; openfiles needs a pre-enabled global flag;
handle.exe is external and elevation-bound).
G-028: a punkboot::utils helper returns the locking processes via the
Windows Restart Manager API (the installers-grade answer to "who is
blocking this file"), with twapi or cffi required lazily at call time -
punkboot::utils stays pure Tcl per the bootsupport no-compiled-extensions
contract, and unavailability degrades to the existing message. make.tcl
kit deploy failures append the locker report when determinable. Recurring
customer: G-023 versioned/dev binaries rewritten every build.
Assisted-by: harness=claude; primary-model=claude-fable-5; api-location=anthropic.com