v2.1.21

Commits

• cb678b9 release: 2.1.21
• 1a9e2ac test(F-939): the live-port e2e uses a spawned session as its source
• 11b2c2f fix(F-939): guard closes its socket on any reader failure, skips bad frames, bypasses system proxies; skip one bad cookie; port-seed test
• 5bee20f fix(F-939): a closed guard connection is the normal end, not a warning
• 5bc0b12 test(F-939): wait for the scripted attach before closing the guard
• d825289 fix(F-939): clones never rotate Google cookies and seed live cookies from the running master