feat(api): add #[non_exhaustive] to public types likely to evolve

ForwardingAction, TargetPattern, ForwardingRule, OperationType,
InterfaceConfig, InterfaceKind, DynamicConfig, and CallError are all
likely to gain variants/fields in future phases. Marking them
#[non_exhaustive] now prevents downstream breakage when new
variants/fields are added. Added constructor methods for types that
are constructed from other crates.

crates/alknet-core/src/config/dynamic_config.rs

@@ -229,6 +229,7 @@ impl Default for RateLimitConfig {
 }
 
 #[derive(Debug, Clone)]
+#[non_exhaustive]
 pub struct DynamicConfig {
     pub auth: AuthPolicy,
     pub forwarding: ForwardingPolicy,
@@ -244,6 +245,18 @@ impl DynamicConfig {
         }
     }
 
+    pub fn from_parts(
+        auth: AuthPolicy,
+        forwarding: ForwardingPolicy,
+        rate_limits: RateLimitConfig,
+    ) -> Self {
+        Self {
+            auth,
+            forwarding,
+            rate_limits,
+        }
+    }
+
     pub fn with_forwarding_policy(mut self, policy: ForwardingPolicy) -> Self {
         self.forwarding = policy;
         self