fix: make retrieval options modal scroll on desktop

The upload and edit-config modals dropped their height cap on sm+ screens (sm:max-h-none), so an expanded Retrieval options panel overflowed the viewport with no scroll. Keep the max-h cap at all breakpoints (max-h is a cap, not a fixed height, so short modals still size naturally) and let the existing overflow-y-auto content area scroll.

Also fix a tsc error in the RetrievalOptions serialization test (optionsToConfig returns SourceConfig whose retrieval is optional).

frontend/src/settings/SourceConfigModal.tsx

@@ -126,7 +126,8 @@ export default function SourceConfigModal({
       title={t('settings.sources.configModal.title')}
       size="lg"
       mobileVariant="sheet"
-      className="max-w-[600px] md:w-[80vw] lg:w-[60vw]"
+      className="max-h-[90vh] max-w-[600px] md:w-[80vw] lg:w-[60vw]"
+      contentClassName="max-h-[80vh]"
       isPerformingTask={saving}
     >
       <div className="flex h-full flex-col">

frontend/src/settings/components/RetrievalOptions.test.tsx

@@ -57,9 +57,9 @@ describe('optionsToConfig (write path)', () => {
   });
 
   it('nests prescreen to null when disabled', () => {
-    expect(optionsToConfig(DEFAULT_RETRIEVAL_OPTIONS).retrieval.prescreen).toBe(
-      null,
-    );
+    expect(
+      optionsToConfig(DEFAULT_RETRIEVAL_OPTIONS).retrieval?.prescreen,
+    ).toBe(null);
   });
 
   it('serializes prescreen object when enabled and trims/normalizes model', () => {
@@ -71,13 +71,13 @@ describe('optionsToConfig (write path)', () => {
       batch_size: 7,
       max_keep: 6,
     };
-    const ps = optionsToConfig(v).retrieval.prescreen;
+    const ps = optionsToConfig(v).retrieval?.prescreen;
     expect(ps).not.toBe(null);
     expect(ps?.model).toBe(null);
     expect(ps?.candidate_k).toBe(30);
 
     v.retrieval.prescreen.model = '  gpt-x  ';
-    expect(optionsToConfig(v).retrieval.prescreen?.model).toBe('gpt-x');
+    expect(optionsToConfig(v).retrieval?.prescreen?.model).toBe('gpt-x');
   });
 });
 

frontend/src/upload/Upload.tsx

@@ -918,8 +918,8 @@ function Upload({
       title={t('modals.uploadDoc.label')}
       size="lg"
       mobileVariant="sheet"
-      className="max-h-[90vh] w-11/12 sm:max-h-none sm:w-auto sm:min-w-[600px] md:min-w-[700px]"
-      contentClassName="max-h-[80vh] sm:max-h-none"
+      className="max-h-[90vh] w-11/12 sm:w-auto sm:min-w-[600px] md:min-w-[700px]"
+      contentClassName="max-h-[80vh]"
     >
       <div className="flex w-full flex-col gap-6">
         {!ingestor.type && (