The set-priority skip guard 'isinstance(raw_priority, int) and
raw_priority == priority' treats a stored boolean as a match because
isinstance(True, int) is True and True == 1 (False == 0). So a corrupted
boolean priority short-circuits to 'already has priority N' and is never
rewritten to a real int — contradicting the adjacent comment that
promises corrupted values get repaired. Exclude bools explicitly,
mirroring normalize_priority's own bool guard.
Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>