CMakeLists.txt:
- Native host build by default; Emscripten-target detection plumbed but
WASM emit deferred to stream 7 (playground build script).
- Header-only INTERFACE library `nisps_core`.
- Host test executable `nisps_core_tests` compiled with -Wall -Wextra
-Werror -Wpedantic (Chris's rules: clean build is non-negotiable).
tests/cpp/test_helpers.hpp:
- Minimal NISPS_TEST / NISPS_EXPECT / NISPS_EXPECT_NEAR macros, no external
deps. Rationale documented in-file: Catch2/doctest would add ~10MB and 30s
for what is currently <100 LOC of test runtime.
22 unit tests covering FixedBuffer (5), RingBuffer (5), Rng (7), math (5).
All green; verified via `cmake --build nisps/build && ./nisps/build/nisps_core_tests`.
