Corrects a false comment example, fixes two tests that couldn't detect their
own regressions, adds two more read-back checkpoints around Main_OnCommand so
a drift report self-locates, guards a spurious zero-vs-zero coincidence match,
and softens two sentences that overclaimed cause or defect.
Corrected the Render-dialog source name the refusal's evidence depends on, added a by-ear content check and a file-size channel proxy, and stopped two comments from overclaiming.
daniel