- Use CodSpeed's codspeed-cpp fork with proper instrumentation for
simulation mode benchmark detection
- setup_codspeed_lib.py creates a flat PlatformIO-compatible library
by combining google_benchmark sources, codspeed core, and
instrument-hooks into a single library directory
- Renames .cc to .cpp (PlatformIO doesn't compile .cc by default)
- Adds all required defines: CODSPEED_ENABLED, CODSPEED_SIMULATION,
CODSPEED_VERSION, CODSPEED_ROOT_DIR, CODSPEED_MODE_DISPLAY
- Output JSON config consumed by cpp_benchmark.py via env var