fix(suppress-warnings): properly restore state in withSuppressedWarnings

Track whether warning type was already suppressed before modification.
Only remove from suppressedWarnings set if this function added it.
Ensures proper cleanup and restoration of original process.emitWarning state.

Author: jdalton

src/suppress-warnings.ts

@@ -144,11 +144,16 @@ export async function withSuppressedWarnings<T>(
   warningType: string,
   callback: () => T | Promise<T>,
 ): Promise<T> {
+  const wasAlreadySuppressed = suppressedWarnings.has(warningType)
   const original = process.emitWarning
   suppressWarningType(warningType)
   try {
     return await callback()
   } finally {
+    // Only remove from suppressed set if we added it.
+    if (!wasAlreadySuppressed) {
+      suppressedWarnings.delete(warningType)
+    }
     process.emitWarning = original
   }
 }