fix: restore T20-stripped print() calls in cosim scripts; add 60 mem validation tests

- Restored print() output in 6 generator/cosim scripts that ruff T20
  had silently stripped, leaving dead 'for _var: pass' stubs and
  orphaned expressions. Files restored from pre-ruff commit and
  re-linted with T20/ERA/ARG/E501 per-file-ignores.
- Removed 5 dead/self-blessing scripts (compare.py, compare_doppler.py,
  compare_mf.py, validate_mem_files.py, LUT.py).
- Added test_mem_validation.py: 60 pytest tests validating .mem files
  against independently-derived ground truth (twiddle factors, chirp
  waveforms, memory addressing, segment padding).
- Updated CI cross-layer-tests job to include test_mem_validation.py.
- All 150 tests pass (61 GUI + 29 cross-layer + 60 mem validation).

pyproject.toml

@@ -49,5 +49,7 @@ select = [
 "**/test_*.py" = ["ARG", "T20", "ERA"]
 # Re-export modules: unused imports are intentional
 "**/v7/hardware.py" = ["F401"]
-# CLI tool: print() is the intentional output mechanism
+# CLI tools & cosim scripts: print() is the intentional output mechanism
 "**/uart_capture.py" = ["T20"]
+"**/tb/cosim/**" = ["T20", "ERA", "ARG", "E501"]
+"**/tb/gen_mf_golden_ref.py" = ["T20", "ERA"]