Implement profile inheritance

src/errors.rs

@@ -21,6 +21,7 @@ pub enum SandboxError {
         source: toml::de::Error,
     },
     ProfileNotFound(String),
+    ProfileCycle(Vec<String>),
     ConflictingMode,
     ConflictingEnvKey(String),
     InvalidEnvEntry(String),
@@ -65,6 +66,13 @@ impl std::fmt::Display for SandboxError {
                 write!(f, "cannot parse config file '{}': {source}", path.display())
             }
             Self::ProfileNotFound(name) => write!(f, "profile not found in config: {name}"),
+            Self::ProfileCycle(chain) => {
+                write!(
+                    f,
+                    "profile inheritance cycle detected: {}",
+                    chain.join(" -> ")
+                )
+            }
             Self::ConflictingMode => write!(
                 f,
                 "config section sets both blacklist and whitelist to true"