feat(sim): add CAM performance sweep test infrastructure

- hw/sim/tests/test_cam_perf.py: new cocotb perf test with bounded wait helpers
- scripts/sweep_cam_perf.py: sweep data model, matrix, and make command builders  
- tests/test_sweep_cam_perf.py: unit tests for sweep helpers
- tests/conftest.py: pytest path configuration for scripts package
- hw/sim/Makefile: deterministic noise params override for perf test compatibility

tests/conftest.py

@@ -0,0 +1,21 @@
+"""pytest configuration — ensure ``scripts/`` is importable via package syntax.
+
+The ``scripts`` directory is a PEP 420 implicit namespace package (no
+``__init__.py``).  Because ``uv run pytest`` does **not** add the project root
+to ``sys.path``, ``from scripts.sweep_cam_perf import ...`` would otherwise
+fail with ``ModuleNotFoundError``.
+
+This conftest inserts the repository root at the front of ``sys.path`` so that
+``scripts`` is discoverable as a top-level package.
+"""
+
+from __future__ import annotations
+
+import sys
+from pathlib import Path
+
+_repo_root = Path(__file__).resolve().parent.parent
+_repo_root_str = str(_repo_root)
+
+if _repo_root_str not in sys.path:
+    sys.path.insert(0, _repo_root_str)