patch_path_invalid· reason_code· applies to event_envelopeAn `ak.schema.patch.v1` patch path violates the ABNF grammar in zh/models/event-and-patch.md §4.2.1 (malformed identifier, quoted identifier, selector or numeric-index form, path > 1024 bytes, or nesting > 16 segments). Parser MUST NOT attempt fallback recovery; reducer rejects with this reason.