Status and minimal next steps

The minimal order of further work is:

1. verify the inherited retarded-coordinate realization on the required source domain;

2. compare it with $X_{\mathrm{cand}}$ using the already proved uniqueness theorem;

3. identify the direct inherited completion and its relation to the reported root and auxiliary scalar values;

4. formulate any further high-frequency, compact-kernel, and free-shell comparison tasks for that actual identified observable.

There is no need to re-prove uniqueness or to leave $I_{\mathrm{cand}}=Q_{\lambda }$ open after importing XVI-F-v3. Conversely, neither result replaces the inherited retarded domain check.