* feat(electron): sign and notarize mac release builds when Apple credentials are present
* fix(electron): work around codesign PID parsing for digit-leading app name in @electron/notarize
codesign interprets a bare '5chan.app' argument as process ID 5, so
@electron/notarize 2.5.0's pre-upload signature check fails with 'No such
process'. Backport the './' basename prefix from electron/notarize#245 as
a yarn patch until forge depends on notarize >= 3.x.
* docs(agent-playbooks): record codesign PID parsing surprise for digit-leading app name
* fix(ci): keep mac signing env consistent with certificate availability