Add explicit environment propagation

docs/NATIVE_V1_SPEC.md

@@ -491,6 +491,8 @@ credential_cache = "~/.local/share/dosh/credentials"
 identity_files = ["~/.ssh/id_ed25519"]
 use_ssh_agent = true
 forward_agent = false
+send_env = ["LANG", "LC_*", "TERM", "COLORTERM"]
+set_env = {}
 forwardings = []
 ```
 
@@ -505,6 +507,7 @@ attach_ticket_ttl_secs = 86400
 allow_tcp_forwarding = true
 allow_remote_forwarding = false
 allow_agent_forwarding = false
+accept_env = ["LANG", "LC_*", "TERM", "COLORTERM"]
 ```
 
 ## 15. Migration Plan