Reject invalid boolean input values (#1160)

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Copilot-Session: c6daa6b5-31f5-46b2-a994-b8320b50a50d

src/util.ts

@@ -20,8 +20,21 @@ export function getTempDir() {
 }
 
 export function getBooleanInput(inputName: string, defaultValue = false) {
-  return (
-    (core.getInput(inputName) || String(defaultValue)).toUpperCase() === 'TRUE'
+  const inputValue = core.getInput(inputName);
+  const normalizedValue = inputValue.trim().toLowerCase();
+
+  if (!normalizedValue) {
+    return defaultValue;
+  }
+  if (normalizedValue === 'true') {
+    return true;
+  }
+  if (normalizedValue === 'false') {
+    return false;
+  }
+
+  throw new Error(
+    `Invalid value '${inputValue}' for boolean input '${inputName}'. Expected 'true' or 'false'.`
   );
 }