tooling: Fix Copilot review comments on devcontainer.

Author: nedseb

.devcontainer/devcontainer.json

@@ -4,9 +4,10 @@
         "dockerfile": "Dockerfile"
     },
 
-    // USB access for STeaMi board (DAPLink / mpremote / OpenOCD)
+    // USB access for STeaMi board (DAPLink / mpremote / OpenOCD).
+    // Privileged mode is required for firmware flashing and board communication.
+    // This is incompatible with GitHub Codespaces but essential for local use.
     "privileged": true,
-    "mounts": ["type=bind,source=/dev/bus/usb,target=/dev/bus/usb"],
     "runArgs": ["--device=/dev/bus/usb"],
 
     "features": {