Release 2.0.1: Portfolio Discovery + CLI Exit Code Fixes

Issue #32: Stop token Portfolio Discovery validates generic fix across all models
- Auto-discovers MLX chat models in HF_HOME with 4-filter validation
- RAM-aware testing (40-70% budgets) prevents OOM
- Empirical report generation (stop_token_config_report.json)
- Fallback to 3 predefined models without HF_HOME
- Implementation: tests_2.0/test_stop_tokens_live.py (~110 LOC)

Issue #38: CLI exit codes now propagate run command errors correctly
- Both text and JSON modes return exit code 1 on model execution failures
- Fixed: run_model() now returns error strings in both modes
- Implementation: mlxk2/operations/run.py + mlxk2/cli.py error detection
- New tests: tests_2.0/test_cli_run_exit_codes.py (9 comprehensive tests)

Testing: 306 passed, 20 skipped (zero regressions)
Docs: Updated README, TESTING, SECURITY for 2.0.1 stable release
Version: 2.0.0 → 2.0.1 (mlxk2/__init__.py)

README.md

@@ -4,9 +4,9 @@
   <img src="https://github.com/mzau/mlx-knife/raw/main/mlxk-demo.gif" alt="MLX Knife Demo" width="900">
 </p>
 
-**Current Stable Version: 2.0.0**
+**Current Stable Version: 2.0.1**
 
-[![GitHub Release](https://img.shields.io/badge/version-2.0.0-green.svg)](https://github.com/mzau/mlx-knife/releases)
+[![GitHub Release](https://img.shields.io/badge/version-2.0.1-green.svg)](https://github.com/mzau/mlx-knife/releases)
 [![License: Apache 2.0](https://img.shields.io/badge/License-Apache%202.0-blue.svg)](https://www.apache.org/licenses/LICENSE-2.0)
 [![Python 3.9+](https://img.shields.io/badge/python-3.9+-blue.svg)](https://www.python.org/downloads/)
 [![Apple Silicon](https://img.shields.io/badge/Apple%20Silicon-green.svg)](https://support.apple.com/en-us/HT211814)
@@ -46,7 +46,7 @@ MLX Knife has been comprehensively tested and verified on:
 pip install mlx-knife
 
 # Verify installation
-mlxk --version  # → mlxk 2.0.0
+mlxk --version  # → mlxk 2.0.1
 ```
 
 ### Development Installation
@@ -60,7 +60,7 @@ cd mlx-knife
 pip install -e ".[dev,test]"
 
 # Verify installation
-mlxk --version  # → mlxk 2.0.0
+mlxk --version  # → mlxk 2.0.1
 
 # Run tests and quality checks (before committing)
 pytest -v
@@ -574,6 +574,6 @@ Apache License 2.0 — see `LICENSE` (root) and `mlxk2/NOTICE`.
 
 <p align="center">
   <b>Made with ❤️ by The BROKE team <img src="broke-logo.png" alt="BROKE Logo" width="30" style="vertical-align: middle;"></b><br>
-  <i>Version 2.0.0 | November 2025</i><br>
+  <i>Version 2.0.1 | November 2025</i><br>
   <a href="https://github.com/mzau/broke-cluster">🔮 Next: BROKE Cluster for multi-node deployments</a>
 </p>