Replace setenv with env list supporting host passthrough

src/errors.rs

@@ -22,6 +22,8 @@ pub enum SandboxError {
     },
     ProfileNotFound(String),
     ConflictingMode,
+    ConflictingEnvKey(String),
+    InvalidEnvEntry(String),
     UnknownConfigKey(String),
     ConfigPathNotAbsolute(PathBuf),
     InvalidBwrapArg(String),
@@ -65,6 +67,12 @@ impl std::fmt::Display for SandboxError {
                 f,
                 "config section sets both blacklist and whitelist to true"
             ),
+            Self::ConflictingEnvKey(key) => {
+                write!(f, "conflicting environment variable options for key: {key}")
+            }
+            Self::InvalidEnvEntry(raw) => {
+                write!(f, "invalid env entry (expected KEY or KEY=VALUE): {raw:?}")
+            }
             Self::UnknownConfigKey(key) => write!(f, "unknown config key: {key}"),
             Self::ConfigPathNotAbsolute(p) => {
                 write!(f, "config path is not absolute: {}", p.display())