docs(row253): record static approval and pre-confirmation residual

agents/gander/work/queue-253/BUILD.md

@@ -193,3 +193,5 @@ M1: BUILD-LOG.md is removed from MANIFEST.sha256. Its row253 phase lines land as
 N4: SID confirmation now waits within the existing inner watchdog budget rather than only 100 sleeps. It still refuses a vanished/unreadable child or unconfirmed session, and the independent outer bound remains. N1/N2 are explicitly deferred in the existing F5 entry to row276 / #1781, as Sage rules. No case1 analogue checks were added in this delta.
 
 The required gate base is the refactor tip Sage names at CLEAR, 378a76b85 or later. This delta is prepared on the current seat branch for static review only; no old-base gate is authorized. The final integrated gate candidate will get fresh hashes and integration records before execution. c4/delta-0112/ freezes the seven source/test/doc paths, the delta from aa81ca390, and static uniqueness. Prior frozen packets remain unchanged.
+
+Duckworth-0113 approves 761893dac after git reads only (8d3fa3f20). B1 and M1 are closed; real timing remains unverified until the gate. N5 is harmless diagnostic noise on a vanished stat entry: the input redirection can report before stderr is redirected, and tester_capture discards supervisor stderr. No source change is made for it. N6 is recorded with R3: if the inner watchdog expires before kernel SID confirmation, finish has only the known child PID and kills that PID, not an unverified session. Other members may remain. Root still refuses, discards stdout and waits only within the outer bound. This is an explicit limit of cleanup before session identity is established, not a claim that the session was swept. The independent outer bound does not prove cross-session cleanup. Source/test bytes and the seven-entry manifest remain exactly those approved at 761893dac.