Use steam ID for reliable, persistent CL user auth

auth/Cargo.toml

@@ -3,6 +3,10 @@ name = "auth"
 version = "0.1.0"
 edition = "2021"
 
+[features]
+steam = ["steamworks"]
+default = []
+
 [dependencies]
 rocket.workspace = true
 libfj.workspace = true
@@ -10,3 +14,5 @@ log.workspace = true
 env_logger.workspace = true
 uuid = { version = "1.12", features = [ "v4", "fast-rng" ] }
 rocket-client-addr = "0.5"
+steamworks = { version = "0.11", optional = true }
+hex = "0.4"