refactor: streamline worker count validation

- Introduced a `clamp_worker_count` function to centralize the logic for enforcing the minimum worker count.
- Updated setter methods in `TreeConfig` to utilize the new clamping function, improving code readability and maintainability.

crates/engine/primitives/src/config.rs

@@ -12,6 +12,17 @@ pub const DEFAULT_MAX_PROOF_TASK_CONCURRENCY: u64 = 256;
 /// Minimum number of workers we allow configuring explicitly.
 pub const MIN_WORKER_COUNT: usize = 2;
 
+/// Clamps the worker count to the minimum allowed value.
+///
+/// Ensures that the worker count is at least [`MIN_WORKER_COUNT`].
+const fn clamp_worker_count(count: usize) -> usize {
+    if count >= MIN_WORKER_COUNT {
+        count
+    } else {
+        MIN_WORKER_COUNT
+    }
+}
+
 /// Returns the default number of storage worker threads based on available parallelism.
 fn default_storage_worker_count() -> usize {
     #[cfg(feature = "std")]
@@ -499,11 +510,7 @@ impl TreeConfig {
 
     /// Setter for the number of storage proof worker threads.
     pub const fn with_storage_worker_count(mut self, storage_worker_count: usize) -> Self {
-        self.storage_worker_count = if storage_worker_count >= MIN_WORKER_COUNT {
-            storage_worker_count
-        } else {
-            MIN_WORKER_COUNT
-        };
+        self.storage_worker_count = clamp_worker_count(storage_worker_count);
         self
     }
 
@@ -514,11 +521,7 @@ impl TreeConfig {
 
     /// Setter for the number of account proof worker threads.
     pub const fn with_account_worker_count(mut self, account_worker_count: usize) -> Self {
-        self.account_worker_count = if account_worker_count >= MIN_WORKER_COUNT {
-            account_worker_count
-        } else {
-            MIN_WORKER_COUNT
-        };
+        self.account_worker_count = clamp_worker_count(account_worker_count);
         self
     }
 }