fix: reopen result modal from progress bar, faster progress, handle LLM context error

- Move import modal visibility into ImportContext so the Layout
  progress pill can reopen the result dialog after the modal was closed.
- Raise LLM progress cap from 85% to 98% and drop the intermediate
  -import 88%- SSE event to eliminate the visual stall after LLM finishes.
- Detect LLM context-length errors (n_keep >= n_ctx) and surface a
  clear message instead of generic -Временная ошибка конвертации-.

frontend/src/components/ImportModal.tsx

@@ -66,13 +66,11 @@ export function ImportModal({ onClose, onDone }: Props) {
         onClose();
       }
     } else {
-      if (result || importState.error) clearImport();
       onClose();
     }
   };
 
   const handleDone = () => {
-    clearImport();
     onDone();
   };
 

frontend/src/components/Layout.tsx

@@ -4,7 +4,7 @@ import { useAuth } from '../context/AuthContext';
 import { useImport } from '../context/ImportContext';
 
 function ImportProgressBar() {
-  const { importState, clearImport } = useImport();
+  const { importState, clearImport, openModal } = useImport();
   const [visible, setVisible] = useState(false);
   const hideTimerRef = useRef<ReturnType<typeof setTimeout> | undefined>(undefined);
 
@@ -31,9 +31,9 @@ function ImportProgressBar() {
 
   const handleClick = useCallback(() => {
     if (hideTimerRef.current) clearTimeout(hideTimerRef.current);
+    openModal();
     setVisible(false);
-    clearImport();
-  }, [clearImport]);
+  }, [openModal]);
 
   if (!visible) return null;
 

frontend/src/context/ImportContext.tsx

@@ -20,6 +20,9 @@ export interface ImportProgress {
 
 interface ImportContextValue {
   importState: ImportProgress;
+  showModal: boolean;
+  openModal: () => void;
+  closeModal: () => void;
   startImport: (file: File) => void;
   clearImport: () => void;
 }
@@ -35,8 +38,12 @@ const ImportContext = createContext<ImportContextValue | null>(null);
 
 export function ImportProvider({ children }: { children: ReactNode }) {
   const [importState, setImportState] = useState<ImportProgress>(INITIAL);
+  const [showModal, setShowModal] = useState(false);
   const runningRef = useRef(false);
 
+  const openModal = useCallback(() => setShowModal(true), []);
+  const closeModal = useCallback(() => setShowModal(false), []);
+
   const startImport = useCallback((file: File) => {
     if (runningRef.current) return;
     runningRef.current = true;
@@ -92,7 +99,9 @@ export function ImportProvider({ children }: { children: ReactNode }) {
   }, []);
 
   return (
-    <ImportContext.Provider value={{ importState, startImport, clearImport }}>
+    <ImportContext.Provider value={{
+      importState, showModal, openModal, closeModal, startImport, clearImport,
+    }}>
       {children}
     </ImportContext.Provider>
   );

frontend/src/pages/HistoryPage.tsx

@@ -18,6 +18,7 @@ import { TransactionTable } from '../components/TransactionTable';
 import { Pagination } from '../components/Pagination';
 import { EditTransactionModal } from '../components/EditTransactionModal';
 import { ImportModal } from '../components/ImportModal';
+import { useImport } from '../context/ImportContext';
 import { toISODate } from '../utils/format';
 
 const PARAM_KEYS = [
@@ -125,7 +126,7 @@ export function HistoryPage() {
   const [accounts, setAccounts] = useState<Account[]>([]);
   const [categories, setCategories] = useState<Category[]>([]);
   const [editingTx, setEditingTx] = useState<Transaction | null>(null);
-  const [showImport, setShowImport] = useState(false);
+  const { showModal: showImport, openModal: openImport, closeModal: closeImport, clearImport } = useImport();
 
   useEffect(() => {
     getAccounts().then(setAccounts).catch(() => {});
@@ -197,7 +198,8 @@ export function HistoryPage() {
   };
 
   const handleImportDone = () => {
-    setShowImport(false);
+    closeImport();
+    clearImport();
     fetchData();
     getAccounts().then(setAccounts).catch(() => {});
   };
@@ -208,7 +210,7 @@ export function HistoryPage() {
         <h1>История операций</h1>
         <button
           className="btn btn-primary"
-          onClick={() => setShowImport(true)}
+          onClick={openImport}
         >
           Импорт выписки
         </button>
@@ -262,7 +264,7 @@ export function HistoryPage() {
 
       {showImport && (
         <ImportModal
-          onClose={() => setShowImport(false)}
+          onClose={closeImport}
           onDone={handleImportDone}
         />
       )}