Parses a parent Task's debug state from its InputPayload bag.
Mirrors ParseTaskGraphParentMetadata's posture exactly: unparseable input is a legitimate state
(a row predating this, a hand edit), and the right reading of "I don't know" is "not being
debugged" — never a throw, and never a guess that could gate real work on garbage.
Parses a parent Task's debug state from its
InputPayloadbag.Mirrors
ParseTaskGraphParentMetadata's posture exactly: unparseable input is a legitimate state (a row predating this, a hand edit), and the right reading of "I don't know" is "not being debugged" — never a throw, and never a guess that could gate real work on garbage.