Initial commit: NexusOS project + desktop theme baseline

Captures the known-good state after theme consolidation and
consistency reconciliation:
- NexusOS GTK/xfwm4/icon theme assets (assets/themes, management/Mint-Y-Nexus)
- Tightened right-click menus, visible separators, no menu icons
- assets/themes/install-theme.sh: idempotent restore of all wiring
  (symlinks, xfconf xsettings+xfwm4, GTK 3/4 settings.ini)
- .gitignore excludes venv/ollama/models/runtime/db

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

bin/gen-nvidia-reqs.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python3
+
+import re, subprocess, sys
+from pathlib import Path
+
+NEXUS_ROOT  = Path.home() / "nexus-core"
+NVIDIA_REQS = NEXUS_ROOT / "nvidia_requirements.txt"
+
+CUDA_TO_WHEEL = [
+    ((12, 8), "cu128"),
+    ((12, 6), "cu126"),
+    ((12, 4), "cu124"),
+    ((12, 1), "cu121"),
+    ((11, 8), "cu118"),
+]
+
+def detect_cuda():
+    try:
+        out = subprocess.run(["nvidia-smi"], capture_output=True, text=True, timeout=10).stdout
+        m = re.search(r"CUDA Version:\s*(\d+)\.(\d+)", out)
+        if m:
+            return int(m.group(1)), int(m.group(2))
+    except (FileNotFoundError, subprocess.TimeoutExpired):
+        pass
+    return None, None
+
+def wheel_suffix(major, minor):
+    for (req_major, req_minor), suffix in CUDA_TO_WHEEL:
+        if (major, minor) >= (req_major, req_minor):
+            return suffix
+    return "cu118"
+
+def main():
+    print("Detecting NVIDIA GPU...")
+    major, minor = detect_cuda()
+
+    if major is None:
+        print("Error: nvidia-smi not found or CUDA version unreadable.")
+        print("Ensure NVIDIA drivers are installed and nvidia-smi is on your PATH.")
+        sys.exit(1)
+
+    print(f"CUDA {major}.{minor} detected.")
+    suffix = wheel_suffix(major, minor)
+    print(f"PyTorch wheel: {suffix}")
+
+    NVIDIA_REQS.write_text(f"""\
+# --- Force NVIDIA/CUDA Priority ---
+--index-url https://download.pytorch.org/whl/{suffix}
+--extra-index-url https://pypi.org/simple
+
+-r requirements-base.txt
+
+# GPU Compute Stack
+torch
+torchaudio
+torchvision
+""")
+
+    print(f"\nWritten: {NVIDIA_REQS}")
+    print("Run 'ncp backup' to push it to the router.")
+
+if __name__ == "__main__":
+    main()