Preserve local paths for desktop saves (#5543)

# Summary

- Adds desktop file tracking: local paths are preserved and save buttons
now work as expcted (doing Save/Save As as appropriate)
- Adds logic to track whether files are 'dirty' (they've been modified
by some tool, and not saved to disk yet).
- Improves file state UX (dirty vs saved) and close warnings
- Web behaviour should be unaffected by these changes

## Indicators
Files now have indicators in desktop mode to tell you their state.

### File up-to-date with disk

<img width="318" height="393" alt="image"
src="https://github.com/user-attachments/assets/06325f9a-afd7-4c2f-8a5b-6d11e3093115"
/>

### File modified by a tool but not saved to disk yet

<img width="357" height="385" alt="image"
src="https://github.com/user-attachments/assets/1a7716d9-c6f7-4d13-be0d-c1de6493954b"
/>

### File not tracked on disk

<img width="312" height="379" alt="image"
src="https://github.com/user-attachments/assets/9cffe300-bd9a-4e19-97c7-9b98bebefacc"
/>

# Limitations
- It's a bit weird that we still have files stored in indexeddb in the
app, which are still loadable. We might want to change this behaviour in
the future
- Viewer's Save doesn't persist to disk. I've left that out here because
it'd need a lot of testing to make sure the logic's right with making
sure you can leave the Viewer with applying the changes to the PDF
_without_ saving to disk
- There's no current way to do Save As on a file that has already been
persisted to disk - it's only ever Save. Similarly, there's no way to
duplicate a file.

---------

Co-authored-by: James Brunton <[email protected]>
Co-authored-by: James Brunton <[email protected]>

frontend/src/core/components/tools/editTableOfContents/EditTableOfContentsWorkbenchView.tsx

@@ -15,6 +15,7 @@ import ErrorNotification from '@app/components/tools/shared/ErrorNotification';
 import ResultsPreview from '@app/components/tools/shared/ResultsPreview';
 import BookmarkEditor from '@app/components/tools/editTableOfContents/BookmarkEditor';
 import { useFileActionTerminology } from '@app/hooks/useFileActionTerminology';
+import { downloadFromUrl } from '@app/services/downloadService';
 
 export interface EditTableOfContentsWorkbenchViewData {
   bookmarks: BookmarkNode[];
@@ -177,10 +178,8 @@ const EditTableOfContentsWorkbenchView = ({ data }: EditTableOfContentsWorkbench
               <Group justify="flex-end" gap="sm">
                 {downloadUrl && (
                   <Button
-                    component="a"
-                    href={downloadUrl}
-                    download={downloadFilename ?? undefined}
                     leftSection={<LocalIcon icon='download-rounded' />}
+                    onClick={() => downloadFromUrl(downloadUrl, downloadFilename ?? "download")}
                   >
                     {terminology.download}
                   </Button>

frontend/src/core/components/tools/getPdfInfo/GetPdfInfoResults.tsx

@@ -2,6 +2,7 @@ import { useCallback, useMemo } from 'react';
 import { Alert, Button, Group, Loader, Stack, Text } from '@mantine/core';
 import { useTranslation } from 'react-i18next';
 import type { GetPdfInfoOperationHook } from '@app/hooks/tools/getPdfInfo/useGetPdfInfoOperation';
+import { downloadFile } from '@app/services/downloadService';
 
 interface GetPdfInfoResultsProps {
   operation: GetPdfInfoOperationHook;
@@ -21,14 +22,7 @@ const GetPdfInfoResults = ({ operation, isLoading, errorMessage }: GetPdfInfoRes
   const selectedDownloadLabel = useMemo(() => t('getPdfInfo.downloadJson', 'Download JSON'), [t]);
 
   const handleDownload = useCallback((file: File) => {
-    const blobUrl = URL.createObjectURL(file);
-    const link = document.createElement('a');
-    link.href = blobUrl;
-    link.download = file.name;
-    document.body.appendChild(link);
-    link.click();
-    document.body.removeChild(link);
-    URL.revokeObjectURL(blobUrl);
+    void downloadFile({ data: file, filename: file.name });
   }, []);
 
   if (isLoading && operation.results.length === 0) {
@@ -76,4 +70,3 @@ const GetPdfInfoResults = ({ operation, isLoading, errorMessage }: GetPdfInfoRes
 
 export default GetPdfInfoResults;
 
-

frontend/src/core/components/tools/shared/ReviewToolStep.tsx

@@ -9,6 +9,9 @@ import { ToolOperationHook } from "@app/hooks/tools/shared/useToolOperation";
 import { Tooltip } from "@app/components/shared/Tooltip";
 import { useFileActionTerminology } from "@app/hooks/useFileActionTerminology";
 import { useFileActionIcons } from "@app/hooks/useFileActionIcons";
+import { saveOperationResults } from "@app/services/operationResultsSaveService";
+import { useFileActions, useFileState } from "@app/contexts/FileContext";
+import { FileId } from "@app/types/fileContext";
 
 export interface ReviewToolStepProps<TParams = unknown> {
   isVisible: boolean;
@@ -34,6 +37,8 @@ function ReviewStepContent<TParams = unknown>({
   const icons = useFileActionIcons();
   const DownloadIcon = icons.download;
   const stepRef = useRef<HTMLDivElement>(null);
+  const { actions: fileActions } = useFileActions();
+  const { selectors } = useFileState();
 
   const handleUndo = async () => {
     try {
@@ -50,6 +55,31 @@ function ReviewStepContent<TParams = unknown>({
       thumbnail: operation.thumbnails[index],
     })) || [];
 
+  const handleDownload = async () => {
+    if (!operation.downloadUrl) return;
+    try {
+      await saveOperationResults({
+        downloadUrl: operation.downloadUrl,
+        downloadFilename: operation.downloadFilename || "download",
+        downloadLocalPath: operation.downloadLocalPath,
+        outputFileIds: operation.outputFileIds,
+        getFile: (fileId) => selectors.getFile(fileId as FileId),
+        getStub: (fileId) => selectors.getStirlingFileStub(fileId as FileId),
+        markSaved: (fileId, savedPath) => {
+          const stub = selectors.getStirlingFileStub(fileId as FileId);
+          fileActions.updateStirlingFileStub(fileId as FileId, {
+            localFilePath: stub?.localFilePath ?? savedPath,
+            isDirty: false
+          });
+        }
+      });
+    } catch (error) {
+      const message = error instanceof Error ? error.message : String(error);
+      console.error("[ReviewToolStep] Failed to download file:", message);
+      alert(`Failed to download file: ${message}`);
+    }
+  };
+
   // Auto-scroll to bottom when content appears
   useEffect(() => {
     if (stepRef.current && (previewFiles.length > 0 || operation.downloadUrl || operation.errorMessage)) {
@@ -92,13 +122,11 @@ function ReviewStepContent<TParams = unknown>({
       )}
       {operation.downloadUrl && (
         <Button
-          component="a"
-          href={operation.downloadUrl}
-          download={operation.downloadFilename}
           leftSection={<DownloadIcon />}
           color="blue"
           fullWidth
           mb="md"
+          onClick={handleDownload}
         >
           {terminology.download}
         </Button>

frontend/src/core/components/tools/showJS/utils.ts

@@ -1,3 +1,5 @@
+import { downloadFromUrl } from "@app/services/downloadService";
+
 export type ShowJsTokenType = "kw" | "str" | "num" | "com" | "plain";
 export type ShowJsToken = { type: ShowJsTokenType; text: string };
 
@@ -372,11 +374,6 @@ export async function copyTextToClipboard(text: string, fallbackElement?: HTMLEl
   }
 }
 
-export function triggerDownload(url: string, filename: string): void {
-  const a = document.createElement("a");
-  a.href = url;
-  a.download = filename;
-  document.body.appendChild(a);
-  a.click();
-  document.body.removeChild(a);
+export async function triggerDownload(url: string, filename: string): Promise<void> {
+  await downloadFromUrl(url, filename);
 }

frontend/src/core/components/tools/validateSignature/ValidateSignatureResults.tsx

@@ -6,6 +6,7 @@ import type { ValidateSignatureOperationHook } from '@app/hooks/tools/validateSi
 import '@app/components/tools/validateSignature/reportView/styles.css';
 import FitText from '@app/components/shared/FitText';
 import { SuggestedToolsSection } from '@app/components/tools/shared/SuggestedToolsSection';
+import { downloadFile } from '@app/services/downloadService';
 
 interface ValidateSignatureResultsProps {
   operation: ValidateSignatureOperationHook;
@@ -80,14 +81,7 @@ const ValidateSignatureResults = ({
   ];
 
   const handleDownload = useCallback((file: File) => {
-    const blobUrl = URL.createObjectURL(file);
-    const link = document.createElement('a');
-    link.href = blobUrl;
-    link.download = file.name;
-    document.body.appendChild(link);
-    link.click();
-    document.body.removeChild(link);
-    URL.revokeObjectURL(blobUrl);
+    void downloadFile({ data: file, filename: file.name });
   }, []);
 
   // Show the big loader only while we're still waiting for the first results.