scope_test.cpp (69 tests) and scope_test_security.cpp (26 tests) are each split into focused files to improve build parallelism and make it easier to locate tests by category:

scope_test_invocation.cpp — $where/$function/$accumulator/mapReduce
scope_test_date.cpp — Date.now() behaviour and millis round-trips
scope_test_getters_setters.cpp — get/set for all BSON types
scope_test_lifecycle.cpp — reset, kill, init, createFunction, bridge
scope_test_helpers.cpp — isolation, array helpers, type(), setElement, getRegEx
scope_test_memory_limits.cpp — store/heap constraints and emit-buffer limits
scope_test_oom_timeout_exec.cpp — OOM detection, timeouts, exec()
scope_test_concurrency.cpp — concurrent scope/pool/kill tests
scope_test_security.cpp — frozen constructors, cross-request isolation, idle bridge

BUILD.bazel gains one mongo_cc_unit_test target per file; scope_test.cpp is emptied (kept to avoid breaking any external references to the file). Total test count unchanged: 95.

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