fix(host): a connector mask that cannot be installed keeps the previous one (#1271 §4) #1281

Duplicate, closed — this anchor was created a minute after the real one.

§4's closure anchor is #1280 ("#1271 §4：hideConnectorTools 的 catch 改 fail-closed"), created 10:44:17Z by Triage; this one (10:45:15Z) was written before I saw it. PR #1274 should name Fixes #1280.

Nothing is lost: no PR references this issue, and it is not a sub-issue of #1271.