Package stager generates TCP stager binaries at runtime.
Shellcode is assembled directly in Go (like Metasm) and wrapped in a
minimal ELF with fake section headers. No external compiler needed.
The payload stream is XOR-encrypted with a per-generation random key.
Generate builds a TCP stager ELF for the given OS/arch with host:port
baked into the shellcode. Returns the binary and its XOR key - the server
must encrypt the payload stream with this key.