Stability checkpoint — svc 1.0.54 (wave 5 SB3+J17 fixes) Captures !195 (wave 5) : - SB3 antrun config : add J17 test overlay copy step (was missing, only in compat profile antrun) → fixes compat-sb3-java17 AggregationServicePropertyTest J21+ try-with-resources/VirtualThreads compile error - Pin checkstyle 10.21.0 in java17 profile (was 13.4.0 = J21 bytecode → J17 UnsupportedClassVersionError on compat-sb4-java17 + compat-sb3-java17) Local validation pre-merge : - ./mvnw verify -DskipTests -Djacoco.skip=true → green (J25 + 13.4.0) - ./mvnw -Dcompat -Djava17 verify -DskipTests -Djacoco.skip=true → green (J17 + 10.21.0) Compat re-trigger needed post-tag to validate. Remaining structural debt : CustomerControllerTest constructor diff (10 vs 6 params between SB3 overlay and main) — wave 6 multi-hour deferred.