initial commit: standalone SoftEther VPN client in Go

Built-in DHCP (raw Ethernet frames through tunnel), automatic reconnection,
host route management, classless static routes (option 121/249), DNS config.
Single static binary, Linux only.

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

README.md

@@ -0,0 +1,27 @@
+# softether-go
+
+Standalone SoftEther VPN client written in Go. Connects to SoftEther VPN servers using the native protocol over TLS, with built-in DHCP, automatic reconnection, and route management. Single static binary, Linux only, zero runtime dependencies beyond `ip` (iproute2).
+
+## Quick start
+
+```bash
+# Build
+go build -o softether-go ./cmd/softether-go/
+
+# Connect
+softether-go -host vpn.example.com -user admin -pass secret \
+  -plain-password -tap vpn0 -accept-default-gateway -accept-dns
+```
+
+## Documentation
+
+See [docs/main.md](docs/main.md) for full documentation:
+
+- [Usage & CLI reference](docs/usage.md)
+- [How it works](docs/architecture.md)
+- [Building](docs/building.md)
+- [Project structure](docs/structure.md)
+
+## License
+
+MIT