fix(frontend): scrollable main region + collapse long run prompts

frontend/src/components/layout/Layout.tsx

@@ -308,7 +308,7 @@ export function Layout() {
       {/* Main */}
       <div className="relative flex-1 flex flex-col overflow-hidden">
         <ConnectionBanner status={sseStatus} retryAttempt={sseRetryAttempt} />
-        <main id="main" className="flex-1 overflow-auto">
+        <main id="main" className="flex-1 min-h-0 overflow-auto">
           <Outlet />
         </main>
       </div>

frontend/src/components/layout/__tests__/Layout.test.tsx

@@ -96,6 +96,13 @@ describe("Layout accessibility", () => {
     expect(screen.getByText("Skip to main content")).toHaveAttribute("href", "#main");
     expect(screen.getByRole("main")).toHaveAttribute("id", "main");
     expect(screen.getByRole("main").parentElement).toHaveClass("relative");
+    // Regression: <main> is a flex item inside a flex-col/overflow-hidden
+    // parent. Without min-h-0, a flex item's default min-height:auto lets it
+    // grow past its allotted space to fit tall content (e.g. a long
+    // generated report) instead of respecting its own overflow-auto -- the
+    // excess then gets hard-clipped by the parent's overflow-hidden with no
+    // scrollbar at all, rather than scrolling into view.
+    expect(screen.getByRole("main")).toHaveClass("flex-1", "min-h-0", "overflow-auto");
   });
 
   it("exposes session actions on keyboard focus and labels the rename input", async () => {

frontend/src/i18n/locales/ar.json

@@ -609,6 +609,8 @@
     "runNotFound": "التشغيل غير موجود",
     "runNotFoundDesc": "ربما تم حذف دليل التشغيل، أو ربما لا يمتلك المتصفح حق الوصول إلى API. تحقّق من ضبط مفتاح مصادقة API في الإعدادات عند الوصول عن بُعد.",
     "goBack": "رجوع",
+    "showFullPrompt": "عرض الطلب كاملاً",
+    "showLessPrompt": "عرض أقل",
     "chart": "الرسم البياني",
     "trades": "التداولات",
     "factor": "تحليل العوامل",

frontend/src/i18n/locales/de.json

@@ -614,6 +614,8 @@
     "runNotFound": "Durchlauf nicht gefunden",
     "runNotFoundDesc": "Das Durchlauf-Verzeichnis wurde möglicherweise entfernt oder Ihrem Browser fehlt die API-Zugriffskonfiguration. Prüfen Sie, ob der API-Authentifizierungsschlüssel in den Einstellungen gesetzt ist, falls Sie remote zugreifen.",
     "goBack": "Zurück",
+    "showFullPrompt": "Vollständigen Prompt anzeigen",
+    "showLessPrompt": "Weniger anzeigen",
     "chart": "Diagramm",
     "trades": "Trades",
     "factor": "Faktor-Research",

frontend/src/i18n/locales/en.json

@@ -614,6 +614,8 @@
     "runNotFound": "Run not found",
     "runNotFoundDesc": "The run directory may have been removed, or your browser may not have API access configured. Check that the API authentication key is set in Settings if accessing remotely.",
     "goBack": "Go back",
+    "showFullPrompt": "Show full prompt",
+    "showLessPrompt": "Show less",
     "chart": "Chart",
     "trades": "Trades",
     "factor": "Factor Research",

frontend/src/i18n/locales/es.json

@@ -614,6 +614,8 @@
     "runNotFound": "Ejecución no encontrada",
     "runNotFoundDesc": "El directorio de la ejecución puede haberse eliminado, o tu navegador puede no tener el acceso a la API configurado. Verifica que la clave de autenticación de la API esté configurada en Configuración si accedes de forma remota.",
     "goBack": "Volver",
+    "showFullPrompt": "Ver prompt completo",
+    "showLessPrompt": "Ver menos",
     "chart": "Gráfico",
     "trades": "Operaciones",
     "factor": "Investigación de factores",

frontend/src/i18n/locales/ja.json

@@ -609,6 +609,8 @@
     "runNotFound": "実行が見つかりません",
     "runNotFoundDesc": "実行ディレクトリが削除されたか、ブラウザに API アクセスが設定されていない可能性があります。リモートでアクセスする場合は、設定で API 認証キーが設定されているか確認してください。",
     "goBack": "戻る",
+    "showFullPrompt": "プロンプト全文を表示",
+    "showLessPrompt": "折りたたむ",
     "chart": "チャート",
     "trades": "トレード",
     "factor": "ファクター分析",

frontend/src/i18n/locales/ko.json

@@ -609,6 +609,8 @@
     "runNotFound": "실행을 찾을 수 없음",
     "runNotFoundDesc": "실행 디렉터리가 제거되었거나 브라우저에 API 액세스가 설정되지 않았을 수 있습니다. 원격으로 액세스하는 경우 설정에서 API 인증 키가 설정되어 있는지 확인하세요.",
     "goBack": "뒤로",
+    "showFullPrompt": "전체 프롬프트 보기",
+    "showLessPrompt": "간략히 보기",
     "chart": "차트",
     "trades": "거래",
     "factor": "팩터 분석",

frontend/src/i18n/locales/zh-CN.json

@@ -609,6 +609,8 @@
     "runNotFound": "运行记录未找到",
     "runNotFoundDesc": "运行目录可能已被删除，或者浏览器未配置 API 访问。如果远程访问，请检查设置中的 API 认证密钥是否已设置。",
     "goBack": "返回",
+    "showFullPrompt": "显示完整提示词",
+    "showLessPrompt": "收起",
     "chart": "图表",
     "trades": "交易",
     "factor": "因子研究",

frontend/src/pages/RunDetail.tsx

@@ -123,6 +123,10 @@ export function RunDetail() {
   const { t } = useTranslation();
   const [run, setRun] = useState<RunData | null>(null);
   const [code, setCode] = useState<Record<string, string>>({});
+  // The prompt header sits above the scrollable body (flex-1 min-h-0
+  // overflow-auto), so an unclamped multi-paragraph prompt eats most of the
+  // viewport and leaves almost no room for the tabs/dashboard below it.
+  const [promptExpanded, setPromptExpanded] = useState(false);
   const [tab, setTab] = useState<Tab>(requestedInitialTab);
   const [loading, setLoading] = useState(true);
   const [selectedSymbol, setSelectedSymbol] = useState("");
@@ -164,6 +168,7 @@ export function RunDetail() {
     cancelBulkChartLoadRef.current = true;
     setRun(null);
     setCode({});
+    setPromptExpanded(false);
     setTab(requestedInitialTab);
     setLoading(true);
     setSelectedSymbol("");
@@ -364,7 +369,21 @@ export function RunDetail() {
           </div>
           {run.elapsed_seconds && <span className="text-xs text-muted-foreground">{run.elapsed_seconds.toFixed(1)}s</span>}
         </div>
-        {run.prompt && <p className="text-sm text-muted-foreground">{run.prompt}</p>}
+        {run.prompt && (
+          <div>
+            <p className={cn("text-sm text-muted-foreground whitespace-pre-wrap", !promptExpanded && "line-clamp-3")}>
+              {run.prompt}
+            </p>
+            <button
+              type="button"
+              aria-expanded={promptExpanded}
+              onClick={() => setPromptExpanded((v) => !v)}
+              className="mt-1 text-xs text-primary hover:underline"
+            >
+              {promptExpanded ? t("runDetail.showLessPrompt") : t("runDetail.showFullPrompt")}
+            </button>
+          </div>
+        )}
         {run.metrics && <MetricsCard metrics={run.metrics as Record<string, number>} />}
 
         <div className="flex flex-wrap items-center gap-1">

frontend/src/pages/__tests__/RunDetail.test.tsx

@@ -142,6 +142,41 @@ describe("RunDetail page", () => {
     expect(screen.queryByText("OLD_CODE")).not.toBeInTheDocument();
   });
 
+  it("collapses an expanded prompt when navigating to another run", async () => {
+    const firstPrompt = "First run prompt\n".repeat(8).trim();
+    const secondPrompt = "Second run prompt\n".repeat(8).trim();
+    apiMock.getRun.mockImplementation((runId: string) => Promise.resolve({
+      status: "success",
+      run_id: runId,
+      prompt: runId === "first" ? firstPrompt : secondPrompt,
+    }));
+    apiMock.getRunCode.mockResolvedValue({});
+
+    const router = renderRunDetail("/runs/first");
+    const expandButton = await screen.findByRole("button", { name: "Show full prompt" });
+    const firstPromptElement = expandButton.previousElementSibling;
+    expect(firstPromptElement).toHaveTextContent("First run prompt");
+    expect(firstPromptElement).toHaveClass("line-clamp-3");
+    expect(expandButton).toHaveAttribute("aria-expanded", "false");
+
+    fireEvent.click(expandButton);
+    expect(firstPromptElement).not.toHaveClass("line-clamp-3");
+    expect(screen.getByRole("button", { name: "Show less" })).toHaveAttribute(
+      "aria-expanded",
+      "true",
+    );
+
+    await act(async () => {
+      await router.navigate("/runs/second");
+    });
+
+    const secondExpandButton = await screen.findByRole("button", { name: "Show full prompt" });
+    const secondPromptElement = secondExpandButton.previousElementSibling;
+    expect(secondPromptElement).toHaveTextContent("Second run prompt");
+    expect(secondPromptElement).toHaveClass("line-clamp-3");
+    expect(secondExpandButton).toHaveAttribute("aria-expanded", "false");
+  });
+
   it("ignores a chart response that finishes after the route changes", async () => {
     const oldChart = deferred<RunData>();
     apiMock.getRun.mockImplementation((runId: string, params: Record<string, string>) => {