- Add Makefile with cocotb configuration for popcount_pipeline RTL simulation
- Add Python test module with reset, drive/expect helpers
- Test row metadata preservation and bit-count correctness across 7 vectors
- Replace NOISE_GEN_BITS/NOISE_SAMPLE_BITS parameters with unified NOISE_BITS
- Use xorshift128 (random128) instead of xorshift64 for PRNG
- Add flip_mask_next combinational helper for single-cycle mask computation
- Add random_enable signal to advance PRNG only on accepted noisy writes
- Simplify FSM by removing mask_group_idx counter
- Update parameter validation: GROUP_BITS (= HASH_BITS/NOISE_BITS) must equal 64
- Update ref_model.py and tests to match new seed convention: {seed, seed}
- Update Makefile and sweep_noise.py with renamed parameters
- Move load_env_file, parse_timeout_seconds, build_remote_script, and
build_ssh_command to scripts/common.py
- Update remote_docker_run.py to import from common module
- Improves code organization and reusability
- remove OPSX Claude commands for apply, archive, explore, and propose
- remove matching OpenSpec workflow skills under `.claude/skills`
- clean up deprecated experimental workflow integration from `.claude`