v152: the elegant clamp-gated repair policy is WRONG ON THE MERITS - it cuts cost 38.7x but 3 of 4 answer-bearing tilde references sit exactly where it declines to repair. Fragment count was the wrong axis. Content-triggered repair dominates: full coverage for 8.6x less than ungated. Caught an impossible-sign attribution error and 5 guard gaps incl. a new class - a magnitude comparison cannot detect a vanished quantity. 1202 tests
