Enforce type checking in CI (#4126)

# Description of Changes
Currently, the `tsconfig.json` file enforces strict type checking, but
nothing in CI checks that the code is actually correctly typed. [Vite
only transpiles TypeScript
code](https://vite.dev/guide/features.html#transpile-only) so doesn't
ensure that the TS code we're running is correct.

This PR adds running of the type checker to CI and fixes the type errors
that have already crept into the codebase.

Note that many of the changes I've made to 'fix the types' are just
using `any` to disable the type checker because the code is under too
much churn to fix anything properly at the moment. I still think
enabling the type checker now is the best course of action though
because otherwise we'll never be able to fix all of them, and it should
at least help us not break things when adding new code.

Co-authored-by: James <james@crosscourtanalytics.com>

frontend/src/components/fileEditor/FileEditor.tsx

@@ -70,11 +70,11 @@ const FileEditor = ({
   } = fileContext;
 
   // Get file selection context
-  const { 
-    selectedFiles: toolSelectedFiles, 
-    setSelectedFiles: setToolSelectedFiles, 
-    maxFiles, 
-    isToolMode 
+  const {
+    selectedFiles: toolSelectedFiles,
+    setSelectedFiles: setToolSelectedFiles,
+    maxFiles,
+    isToolMode
   } = useFileSelection();
 
   const [files, setFiles] = useState<FileItem[]>([]);
@@ -82,7 +82,7 @@ const FileEditor = ({
   const [error, setError] = useState<string | null>(null);
   const [localLoading, setLocalLoading] = useState(false);
   const [selectionMode, setSelectionMode] = useState(toolMode);
-  
+
   // Enable selection mode automatically in tool mode
   React.useEffect(() => {
     if (toolMode) {
@@ -115,7 +115,7 @@ const FileEditor = ({
 
   // Get selected file IDs from context (defensive programming)
   const contextSelectedIds = Array.isArray(selectedFileIds) ? selectedFileIds : [];
-  
+
   // Map context selections to local file IDs for UI display
   const localSelectedIds = files
     .filter(file => {
@@ -144,33 +144,33 @@ const FileEditor = ({
     // Check if the actual content has changed, not just references
     const currentActiveFileNames = activeFiles.map(f => f.name);
     const currentProcessedFilesSize = processedFiles.size;
-    
+
     const activeFilesChanged = JSON.stringify(currentActiveFileNames) !== JSON.stringify(lastActiveFilesRef.current);
     const processedFilesChanged = currentProcessedFilesSize !== lastProcessedFilesRef.current;
-    
+
     if (!activeFilesChanged && !processedFilesChanged) {
       return;
     }
-    
+
     // Update refs
     lastActiveFilesRef.current = currentActiveFileNames;
     lastProcessedFilesRef.current = currentProcessedFilesSize;
-    
+
     const convertActiveFiles = async () => {
-      
+
       if (activeFiles.length > 0) {
         setLocalLoading(true);
         try {
           // Process files in chunks to avoid blocking UI
           const convertedFiles: FileItem[] = [];
-          
+
           for (let i = 0; i < activeFiles.length; i++) {
             const file = activeFiles[i];
-            
+
             // Try to get thumbnail from processed file first
             const processedFile = processedFiles.get(file);
             let thumbnail = processedFile?.pages?.[0]?.thumbnail;
-            
+
             // If no thumbnail from processed file, try to generate one
             if (!thumbnail) {
               try {
@@ -180,28 +180,28 @@ const FileEditor = ({
                 thumbnail = undefined; // Use placeholder
               }
             }
-            
+
             const convertedFile = {
               id: `file-${Date.now()}-${Math.random()}`,
               name: file.name,
               pageCount: processedFile?.totalPages || Math.floor(Math.random() * 20) + 1,
-              thumbnail,
+              thumbnail: thumbnail || '',
               size: file.size,
               file,
             };
-            
+
             convertedFiles.push(convertedFile);
-            
+
             // Update progress
             setConversionProgress(((i + 1) / activeFiles.length) * 100);
-            
+
             // Yield to main thread between files
             if (i < activeFiles.length - 1) {
               await new Promise(resolve => requestAnimationFrame(resolve));
             }
           }
-              
-          
+
+
           setFiles(convertedFiles);
         } catch (err) {
           console.error('Error converting active files:', err);
@@ -237,7 +237,7 @@ const FileEditor = ({
           try {
             // Validate ZIP file first
             const validation = await zipFileService.validateZipFile(file);
-            
+
             if (validation.isValid && validation.containsPDFs) {
               // ZIP contains PDFs - extract them
               setZipExtractionProgress({
@@ -269,7 +269,7 @@ const FileEditor = ({
 
               if (extractionResult.success) {
                 allExtractedFiles.push(...extractionResult.extractedFiles);
-                
+
                 // Record ZIP extraction operation
                 const operationId = `zip-extract-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
                 const operation: FileOperation = {
@@ -289,10 +289,10 @@ const FileEditor = ({
                   }
                 }
               };
-              
+
               recordOperation(file.name, operation);
               markOperationApplied(file.name, operationId);
-              
+
               if (extractionResult.errors.length > 0) {
                 errors.push(...extractionResult.errors);
               }
@@ -344,7 +344,7 @@ const FileEditor = ({
               }
             }
           };
-          
+
           recordOperation(file.name, operation);
           markOperationApplied(file.name, operationId);
         }
@@ -357,7 +357,7 @@ const FileEditor = ({
       const errorMessage = err instanceof Error ? err.message : 'Failed to process files';
       setError(errorMessage);
       console.error('File processing error:', err);
-      
+
       // Reset extraction progress on error
       setZipExtractionProgress({
         isExtracting: false,
@@ -377,7 +377,7 @@ const FileEditor = ({
 
   const closeAllFiles = useCallback(() => {
     if (activeFiles.length === 0) return;
-    
+
     // Record close all operation for each file
     activeFiles.forEach(file => {
       const operationId = `close-all-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`;
@@ -396,14 +396,14 @@ const FileEditor = ({
           }
         }
       };
-      
+
       recordOperation(file.name, operation);
       markOperationApplied(file.name, operationId);
     });
-    
+
     // Remove all files from context but keep in storage
     removeFiles(activeFiles.map(f => (f as any).id || f.name), false);
-    
+
     // Clear selections
     setContextSelectedFiles([]);
   }, [activeFiles, removeFiles, setContextSelectedFiles, recordOperation, markOperationApplied]);
@@ -411,12 +411,12 @@ const FileEditor = ({
   const toggleFile = useCallback((fileId: string) => {
     const targetFile = files.find(f => f.id === fileId);
     if (!targetFile) return;
-    
+
     const contextFileId = (targetFile.file as any).id || targetFile.name;
     const isSelected = contextSelectedIds.includes(contextFileId);
-    
+
     let newSelection: string[];
-    
+
     if (isSelected) {
       // Remove file from selection
       newSelection = contextSelectedIds.filter(id => id !== contextFileId);
@@ -433,10 +433,10 @@ const FileEditor = ({
         newSelection = [...contextSelectedIds, contextFileId];
       }
     }
-    
+
     // Update context
     setContextSelectedFiles(newSelection);
-    
+
     // Update tool selection context if in tool mode
     if (isToolMode || toolMode) {
       const selectedFiles = files
@@ -572,12 +572,12 @@ const FileEditor = ({
     console.log('handleDeleteFile called with fileId:', fileId);
     const file = files.find(f => f.id === fileId);
     console.log('Found file:', file);
-    
+
     if (file) {
       console.log('Attempting to remove file:', file.name);
       console.log('Actual file object:', file.file);
       console.log('Actual file.file.name:', file.file.name);
-      
+
       // Record close operation
       const fileName = file.file.name;
       const fileId = (file.file as any).id || fileName;
@@ -597,19 +597,16 @@ const FileEditor = ({
           }
         }
       };
-      
+
       recordOperation(fileName, operation);
-      
+
       // Remove file from context but keep in storage (close, don't delete)
       console.log('Calling removeFiles with:', [fileId]);
       removeFiles([fileId], false);
-      
+
       // Remove from context selections
-      setContextSelectedFiles(prev => {
-        const safePrev = Array.isArray(prev) ? prev : [];
-        return safePrev.filter(id => id !== fileId);
-      });
-      
+      const newSelection = contextSelectedIds.filter(id => id !== fileId);
+      setContextSelectedFiles(newSelection);
       // Mark operation as applied
       markOperationApplied(fileName, operationId);
     } else {
@@ -670,7 +667,7 @@ const FileEditor = ({
       accept={["*/*"]}
       multiple={true}
       maxSize={2 * 1024 * 1024 * 1024}
-      style={{ 
+      style={{
         height: '100vh',
         border: 'none',
         borderRadius: 0,
@@ -707,7 +704,7 @@ const FileEditor = ({
         ) : files.length === 0 && (localLoading || zipExtractionProgress.isExtracting) ? (
           <Box>
             <SkeletonLoader type="controls" />
-            
+
             {/* ZIP Extraction Progress */}
             {zipExtractionProgress.isExtracting && (
               <Box mb="md" p="sm" style={{ backgroundColor: 'var(--mantine-color-orange-0)', borderRadius: 8 }}>
@@ -721,10 +718,10 @@ const FileEditor = ({
                 <Text size="xs" c="dimmed" mb="xs">
                   {zipExtractionProgress.extractedCount} of {zipExtractionProgress.totalFiles} files extracted
                 </Text>
-                <div style={{ 
-                  width: '100%', 
-                  height: '4px', 
-                  backgroundColor: 'var(--mantine-color-gray-2)', 
+                <div style={{
+                  width: '100%',
+                  height: '4px',
+                  backgroundColor: 'var(--mantine-color-gray-2)',
                   borderRadius: '2px',
                   overflow: 'hidden'
                 }}>
@@ -737,7 +734,7 @@ const FileEditor = ({
                 </div>
               </Box>
             )}
-            
+
             {/* Processing indicator */}
             {localLoading && (
               <Box mb="md" p="sm" style={{ backgroundColor: 'var(--mantine-color-blue-0)', borderRadius: 8 }}>
@@ -745,10 +742,10 @@ const FileEditor = ({
                   <Text size="sm" fw={500}>Loading files...</Text>
                   <Text size="sm" c="dimmed">{Math.round(conversionProgress)}%</Text>
                 </Group>
-                <div style={{ 
-                  width: '100%', 
-                  height: '4px', 
-                  backgroundColor: 'var(--mantine-color-gray-2)', 
+                <div style={{
+                  width: '100%',
+                  height: '4px',
+                  backgroundColor: 'var(--mantine-color-gray-2)',
                   borderRadius: '2px',
                   overflow: 'hidden'
                 }}>
@@ -761,27 +758,27 @@ const FileEditor = ({
                 </div>
               </Box>
             )}
-            
+
             <SkeletonLoader type="fileGrid" count={6} />
           </Box>
         ) : (
           <DragDropGrid
             items={files}
-            selectedItems={localSelectedIds}
+            selectedItems={localSelectedIds as any /* FIX ME */}
             selectionMode={selectionMode}
             isAnimating={isAnimating}
-          onDragStart={handleDragStart}
-          onDragEnd={handleDragEnd}
-          onDragOver={handleDragOver}
-          onDragEnter={handleDragEnter}
-          onDragLeave={handleDragLeave}
-          onDrop={handleDrop}
-          onEndZoneDragEnter={handleEndZoneDragEnter}
-          draggedItem={draggedFile}
-          dropTarget={dropTarget}
-          multiItemDrag={multiFileDrag}
-          dragPosition={dragPosition}
-          renderItem={(file, index, refs) => (
+            onDragStart={handleDragStart as any /* FIX ME */}
+            onDragEnd={handleDragEnd}
+            onDragOver={handleDragOver}
+            onDragEnter={handleDragEnter as any /* FIX ME */}
+            onDragLeave={handleDragLeave}
+            onDrop={handleDrop as any /* FIX ME */}
+            onEndZoneDragEnter={handleEndZoneDragEnter}
+            draggedItem={draggedFile as any /* FIX ME */}
+            dropTarget={dropTarget as any /* FIX ME */}
+            multiItemDrag={multiFileDrag as any /* FIX ME */}
+            dragPosition={dragPosition}
+            renderItem={(file, index, refs) => (
             <FileThumbnail
               file={file}
               index={index}
@@ -801,8 +798,6 @@ const FileEditor = ({
               onToggleFile={toggleFile}
               onDeleteFile={handleDeleteFile}
               onViewFile={handleViewFile}
-              onMergeFromHere={handleMergeFromHere}
-              onSplitFile={handleSplitFile}
               onSetStatus={setStatus}
               toolMode={toolMode}
               isSupported={isFileSupported(file.name)}
@@ -831,7 +826,6 @@ const FileEditor = ({
         onClose={() => setShowFilePickerModal(false)}
         storedFiles={[]} // FileEditor doesn't have access to stored files, needs to be passed from parent
         onSelectFiles={handleLoadFromStorage}
-        allowMultiple={true}
       />
 
       {status && (