Update install.md

Author: qectorlab

install.md

@@ -22,3 +22,74 @@ For all standard use cases, install the pre-compiled, optimized binary wheel dir
 ```powershell
 py -3.11 -m venv .venv
 .\.venv\Scripts\Activate.ps1
+
+```
+
+**Linux / macOS:**
+
+```bash
+python3 -m venv .venv
+source .venv/bin/activate
+
+```
+
+### 2. Install via PyPI
+
+Upgrade `pip` first to ensure compatibility with modern binary wheels, then install QECTOR:
+
+```bash
+python -m pip install --upgrade pip
+python -m pip install qector-decoder-v3
+
+```
+
+*(Optional)* To install with compatibility layers and benchmarking tools:
+
+```bash
+python -m pip install "qector-decoder-v3[stim,bench]"
+
+```
+
+### 3. Verify Installation
+
+Run the following command to confirm the binary is correctly installed and functioning:
+
+```bash
+python -c "from qector_decoder_v3 import UnionFindDecoder, BlossomDecoder; import qector_decoder_v3; print(f'QECTOR OK - v{qector_decoder_v3.__version__}')"
+
+```
+
+**Expected Output:**
+
+```text
+QECTOR OK - v0.6.6
+
+```
+
+---
+
+## 🏢 Commercial & Source Access
+
+If your institution requires a custom build, specific feature flags (e.g., isolated CUDA/OpenCL configurations), or source-code review for security due diligence, this is **only available under a commercial license or Non-Disclosure Agreement (NDA)**.
+
+To request access to the restricted technical archive or discuss enterprise deployment:
+
+* **Web:** [https://qector.store/pricing](https://qector.store/pricing)
+* **Email:** [admin@qector.store](https://www.google.com/search?q=mailto%3Aadmin%40qector.store)
+
+---
+
+## 🔧 Common Troubleshooting
+
+| Issue | Solution |
+| --- | --- |
+| **`ERROR: Could not find a version that satisfies the requirement`** | Ensure you are using Python 3.9, 3.10, 3.11, or 3.12. Upgrade pip: `python -m pip install --upgrade pip`. |
+| **`ImportError: DLL load failed / .so not found`** | The pre-compiled wheel may be incompatible with highly unusual OS configurations. Ensure you are on a standard 64-bit Windows, Linux, or macOS environment. |
+| **Missing optional dependencies (e.g., `stim`, `pymatching`)** | These are not bundled in the base wheel. Install them explicitly: `python -m pip install stim pymatching sinter`. |
+| **GPU acceleration not detected** | The base PyPI wheel includes CPU and standard GPU fallbacks. For specialized enterprise GPU deployments, contact [admin@qector.store](https://www.google.com/search?q=mailto%3Aadmin%40qector.store) for custom build options. |
+
+---
+
+*© 2024–2026 Guillaume Lessard. All Rights Reserved. Protected by timestamped archival (Zenodo DOI) and commercial licensing terms.*
+
+```