Add Linux support: cross-platform restart, nvidia-ml-py dep, README update

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/api/routes/system.py

@@ -273,19 +273,26 @@ STORE_MAP = {
     "profiles": "profiles_file",
 }
 
-_RESTART_SCRIPT = Path(__file__).resolve().parents[4] / "restart.ps1"
+_SERVER_DIR = Path(__file__).resolve().parents[4]
 
 
 def _schedule_restart() -> None:
-    """Spawn restart.ps1 after a short delay so the HTTP response completes."""
+    """Spawn a restart script after a short delay so the HTTP response completes."""
 
     def _restart():
         import time
         time.sleep(1)
-        subprocess.Popen(
-            ["powershell", "-ExecutionPolicy", "Bypass", "-File", str(_RESTART_SCRIPT)],
-            creationflags=subprocess.DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP,
-        )
+        if sys.platform == "win32":
+            subprocess.Popen(
+                ["powershell", "-ExecutionPolicy", "Bypass", "-File",
+                 str(_SERVER_DIR / "restart.ps1")],
+                creationflags=subprocess.DETACHED_PROCESS | subprocess.CREATE_NEW_PROCESS_GROUP,
+            )
+        else:
+            subprocess.Popen(
+                ["bash", str(_SERVER_DIR / "restart.sh")],
+                start_new_session=True,
+            )
 
     threading.Thread(target=_restart, daemon=True).start()