What has advanced

The complete retained incidence is no longer represented by a temporal monomial or by an unspecified eleven-term symbol sum. It is a precise common-kernel germ with six potentially surviving mixed branches and both gravitational-response legs.

The remaining problem is correspondingly exact: control the grouped composition of that six-branch kernel with the two frozen cross-lines on the retained characteristic relation, including the lower-order terms.

The source and scalar-response branches have not been declared to cancel or to vanish. The $B_6$ numerator has not been promoted to a residue. No additional contact has been chosen to force a value.