Build the seeding CLI from the RDM-pinned backend

Why: task-sync advanced the Dev backend gitlink past the RDM pin; a newer-schema user-create CLI migrates the fresh store beyond what the RDM binary (schema ceiling of its pin) can open.

Evidence: reproduce on 20261011-180439 run (v25 store vs v24 binary); rerun green recorded after this change.

Impact: scripts/e2e.sh only; seeding and serving now share one base version.

scripts/e2e.sh

@@ -83,8 +83,10 @@ trap cleanup EXIT
 (cd "$RDM_WT" && go build -o "$OUT/agent-system-rdm" .) || die "rdm build failed"
 log "rdm binary: $OUT/agent-system-rdm (RDM@${RDM_SHA:0:12}, pins@${PIN_SHA_WANT:0:12})"
 
-log "build base CLI (user create)"
-(cd "$DEV_ROOT/modules/backend" && go build -o "$OUT/agent-system" ./cmd/agent-system) \
+log "build base CLI (user create) from the same pinned backend as the RDM binary"
+# 版本一致性：建号 CLI 必须与被测 RDM 二进制共用同一基座 pin——用 Dev 顶层
+# backend（main 最新）建号会把库迁到更高 schema，RDM pins（较旧）打不开。
+(cd "$RDM_WT/pins/agent-system-backend" && go build -o "$OUT/agent-system" ./cmd/agent-system) \
   || die "backend cli build failed"
 
 log "build frontend dist (contracts + ui deps + bundle, via make frontend)"