Add Go agent OpenWrt service package

agent/package/rmm-agent-go/README.md

@@ -0,0 +1,37 @@
+# rmm-agent-go OpenWrt Package
+
+OpenWrt package skeleton for the Go agent.
+
+## Buildroot Usage
+
+Cross-build the Go binary for the router target first and place it into the package-local files directory:
+
+```sh
+mkdir -p agent/package/rmm-agent-go/files/usr/bin
+GOOS=linux GOARCH=mipsle GOMIPS=softfloat go build -trimpath -ldflags="-s -w" -o agent/package/rmm-agent-go/files/usr/bin/rmm-agent-go ./agent/go/cmd/rmm-agent
+```
+
+Copy or symlink this directory into an OpenWrt buildroot package path:
+
+```sh
+cp -R agent/package/rmm-agent-go /path/to/openwrt/package/rmm-agent-go
+cd /path/to/openwrt
+make package/rmm-agent-go/compile V=s
+```
+
+Then install the generated `.ipk` on a router:
+
+```sh
+opkg install /tmp/rmm-agent-go_*.ipk
+vi /etc/rmm-agent-go.conf
+/etc/init.d/rmm-agent-go enable
+/etc/init.d/rmm-agent-go start
+```
+
+## Installed Files
+
+- `/usr/bin/rmm-agent-go`
+- `/etc/init.d/rmm-agent-go`
+- `/etc/rmm-agent-go.conf`
+
+The package intentionally keeps a separate config and service name so it can run side by side with the shell agent during migration.