Ask a secure retriever whether a field is open beside its items

A secure retriever's values are at .../{parameter}/items and its
questions - is the field required, does it take a typed value - at
.../{parameter}/required and /open beside them. The question URL was
made by suffixing the values URL, so for every secure retriever it
pointed under items, where nothing answers: choosing a global input as
a file's source showed an error contacting the server.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/app/services/retriever/retriever-url.spec.ts

@@ -26,4 +26,10 @@ describe('appendRetrieverQuestion', () => {
     expect(appendRetrieverQuestion(undefined, 'open')).toBeNull();
     expect(appendRetrieverQuestion('   ', 'open')).toBeNull();
   });
+  it('asks a secure retriever beside its items, not under them', () => {
+    expect(appendRetrieverQuestion('/secure-retriever/GlobalInputs/inputs/items?type=FILE', 'open'))
+      .toBe('/secure-retriever/GlobalInputs/inputs/open?type=FILE');
+    expect(appendRetrieverQuestion('/secure-retriever/Flows/subFlow/items', 'required'))
+      .toBe('/secure-retriever/Flows/subFlow/required');
+  });
 });

src/app/services/retriever/retriever-url.ts

@@ -17,7 +17,10 @@ export function appendRetrieverQuestion(
   question: RetrieverQuestion
 ): string | null {
   if (typeof rawUrl !== 'string' || rawUrl.trim().length === 0) return null;
-  const [path, queryString] = rawUrl.split('?', 2);
+  const [rawPath, queryString] = rawUrl.split('?', 2);
+  // A secure retriever's values live at `.../{parameter}/items`, its questions at
+  // `.../{parameter}/{question}` beside them - not under `items`, where nothing answers.
+  const path = rawPath.replace(/\/items$/, '');
   const normalizedPath = path.endsWith(`/${question}`) ? path : `${path}/${question}`;
   return queryString ? `${normalizedPath}?${queryString}` : normalizedPath;
 }