feat: add file tree upload progress

Users need a visible upload path from the explorer itself, not only drag and
 drop behavior with no progress feedback. Routing picker and drop uploads
 through one XHR-backed hook keeps progress, validation, refresh, and success
 counts consistent for every upload source.

The 200MB limit is mirrored in the client, multer, and nginx template so large
 uploads fail predictably instead of being blocked by whichever layer sees the
 request first. The server also returns explicit requested and uploaded counts
 so partial or multi-file batches can render accurate status text.

server/index.js

@@ -84,6 +84,9 @@ const __dirname = getModuleDir(import.meta.url);
 // Resolving the app root once keeps every repo-level lookup below aligned across both layouts.
 const APP_ROOT = findAppRoot(__dirname);
 const installMode = fs.existsSync(path.join(APP_ROOT, '.git')) ? 'git' : 'npm';
+const MAX_FILE_UPLOAD_SIZE_MB = 200;
+const MAX_FILE_UPLOAD_SIZE_BYTES = MAX_FILE_UPLOAD_SIZE_MB * 1024 * 1024;
+const MAX_FILE_UPLOAD_COUNT = 20;
 
 console.log('SERVER_PORT from env:', process.env.SERVER_PORT);
 
@@ -897,27 +900,27 @@ const uploadFilesHandler = async (req, res) => {
             }
         }),
         limits: {
-            fileSize: 50 * 1024 * 1024, // 50MB limit
-            files: 20 // Max 20 files at once
+            fileSize: MAX_FILE_UPLOAD_SIZE_BYTES,
+            files: MAX_FILE_UPLOAD_COUNT
         }
     });
 
     // Use multer middleware
-    uploadMiddleware.array('files', 20)(req, res, async (err) => {
+    uploadMiddleware.array('files', MAX_FILE_UPLOAD_COUNT)(req, res, async (err) => {
         if (err) {
             console.error('Multer error:', err);
             if (err.code === 'LIMIT_FILE_SIZE') {
-                return res.status(400).json({ error: 'File too large. Maximum size is 50MB.' });
+                return res.status(400).json({ error: `File too large. Maximum size is ${MAX_FILE_UPLOAD_SIZE_MB}MB.` });
             }
             if (err.code === 'LIMIT_FILE_COUNT') {
-                return res.status(400).json({ error: 'Too many files. Maximum is 20 files.' });
+                return res.status(400).json({ error: `Too many files. Maximum is ${MAX_FILE_UPLOAD_COUNT} files.` });
             }
             return res.status(500).json({ error: err.message });
         }
 
         try {
             const { projectId } = req.params;
-            const { targetPath, relativePaths } = req.body;
+            const { targetPath, relativePaths, requestedFileCount: requestedFileCountRaw } = req.body;
 
             // Parse relative paths if provided (for folder uploads)
             let filePaths = [];
@@ -941,6 +944,11 @@ const uploadFilesHandler = async (req, res) => {
                 return res.status(400).json({ error: 'No files provided' });
             }
 
+            const parsedRequestedFileCount = Number.parseInt(requestedFileCountRaw, 10);
+            const requestedFileCount = Number.isFinite(parsedRequestedFileCount) && parsedRequestedFileCount > 0
+                ? parsedRequestedFileCount
+                : req.files.length;
+
             // Resolve the project directory through the DB using the new projectId.
             const projectRoot = await projectsDb.getProjectPathById(projectId);
             if (!projectRoot) {
@@ -1019,8 +1027,10 @@ const uploadFilesHandler = async (req, res) => {
             res.json({
                 success: true,
                 files: uploadedFiles,
+                uploadedCount: uploadedFiles.length,
+                requestedFileCount,
                 targetPath: resolvedTargetDir,
-                message: `Uploaded ${uploadedFiles.length} file(s) successfully`
+                message: `Uploaded ${uploadedFiles.length} ${uploadedFiles.length === 1 ? 'file' : 'files'} successfully`
             });
         } catch (error) {
             console.error('Error uploading files:', error);