fix(#76): keep embedded Preview from stacking freshness notices

Weekend shell already discloses context availability; a second Preview banner
from shared championship headers produced conflicting Partial/Stale vocabulary.

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend/src/pages/RacePreviewPage.tsx

@@ -455,7 +455,8 @@ export function RacePreviewPage({
       data-meeting-key={previewMeeting.meeting_key}
       data-embedded={embedded ? 'true' : undefined}
     >
-      {dataNotice && (
+      {/* Weekend shell owns availability disclosure when Preview is embedded. */}
+      {!embedded && dataNotice && (
         <DataNotice
           availability={dataNotice}
           message={noticeMessage(dataNotice)}

frontend/src/test/RacePreviewPage.test.tsx

@@ -298,6 +298,8 @@ describe('RacePreviewPage', () => {
     expect(mockFetchMeetings).not.toHaveBeenCalledWith(2099, expect.anything(), expect.anything())
     expect(mockFetchSessions).toHaveBeenCalledWith(100, 'auto', expect.anything())
     expect(screen.queryByTestId('preview-header')).not.toBeInTheDocument()
+    // Weekend shell owns availability disclosure — no stacked Preview notice.
+    expect(screen.queryByTestId('preview-data-notice')).not.toBeInTheDocument()
   })
 
   it('sanitizes raw HTTP errors and offers a guarded keyboard Retry', async () => {

frontend/src/test/WeekendPage.test.tsx

@@ -404,6 +404,9 @@ describe('WeekendPage canonical contract rendering', () => {
     await waitFor(() => expect(screen.getByTestId('preview-page')).toBeInTheDocument())
     expect(screen.getByTestId('preview-page')).toHaveAttribute('data-meeting-key', '2')
     expect(screen.getByTestId('preview-page')).toHaveAttribute('data-embedded', 'true')
+    // Single shell notice — Preview must not stack a second freshness banner.
+    expect(screen.getByTestId('weekend-data-notice')).toHaveTextContent(/Partial/i)
+    expect(screen.queryByTestId('preview-data-notice')).not.toBeInTheDocument()
     // Canonical identity was passed — Preview must not fan out to seasons /
     // current-season meetings selection. Prior-year lookup for "Last year here"
     // remains an intentional supplement.