devcontainer: add bun feature and update postCreateCommand

.devcontainer/devcontainer.json

@@ -2,6 +2,7 @@
 	"name": "MeshCore",
 	"image": "mcr.microsoft.com/devcontainers/python:3-bookworm",
 	"features": {
+		"ghcr.io/devcontainers-extra/features/bun:1": {},
 		"ghcr.io/rocker-org/devcontainer-features/apt-packages:1": {
 			"packages": [
 				"sudo"
@@ -11,14 +12,15 @@
 	"runArgs": [
 		"--privileged",
 		"--network=host",
-		"--volume=/dev/bus/usb:/dev/bus/usb:ro",
-		// arch tty* is owned by uucp (986)
+		"--device=/dev/bus/usb",
+		// arch linux tty* is owned by uucp (986)
+		"--group-add=986",
 		// debian tty* is owned by dialout (20)
-		"--group-add=20",
-		"--group-add=986"
+		"--group-add=20"
 	],
 	"postCreateCommand": {
-		"platformio": "pipx install platformio"
+		"platformio": "pipx install platformio",
+		"opencode": "curl -fsSL https://opencode.ai/install | bash"
 	},
 	"customizations": {
 		"vscode": {