d5cc6bd6fc
Seven near-identical predicate tests collapse into one invariant test (flag OR sentinel name; neither on a normal channel; no flags attribute is not obfuscated) plus the directory-filter test, per the repo's <=2-invariant-tests-per-fix rule. The explicit-id backfill path gets its own regression test in the existing backfill harness (fails on the unfixed code, verified by sabotage).