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.

src/components/file-tree/view/FileTreeUploadProgress.tsx

@@ -0,0 +1,90 @@
+import { AlertCircle, CheckCircle2, Upload } from 'lucide-react';
+import { useTranslation } from 'react-i18next';
+
+import { cn } from '../../../lib/utils';
+import type { FileTreeUploadProgressState } from '../hooks/useFileTreeUpload';
+
+type FileTreeUploadProgressProps = {
+  upload: FileTreeUploadProgressState | null;
+};
+
+const clampProgress = (progress: number) => Math.min(100, Math.max(0, progress));
+
+const pluralizeFiles = (count: number) => (count === 1 ? 'file' : 'files');
+
+export default function FileTreeUploadProgress({ upload }: FileTreeUploadProgressProps) {
+  const { t } = useTranslation();
+
+  if (!upload) {
+    return null;
+  }
+
+  const progress = clampProgress(upload.progress);
+  const isUploading = upload.status === 'uploading';
+  const isComplete = upload.status === 'complete';
+  const isError = upload.status === 'error';
+  const fileSummary =
+    upload.fileCount === 1 && upload.fileName
+      ? upload.fileName
+      : `${upload.fileCount} ${pluralizeFiles(upload.fileCount)}`;
+
+  const title = isUploading
+    ? t('fileTree.uploadingFiles', 'Uploading files')
+    : isComplete
+    ? t('fileTree.uploadComplete', 'Upload complete')
+    : t('fileTree.uploadFailed', 'Upload failed');
+
+  const detail = isError
+    ? upload.error
+    : isComplete && typeof upload.uploadedCount === 'number'
+    ? t('fileTree.uploadedCount', 'Uploaded {{uploaded}} of {{total}} {{label}}', {
+        uploaded: upload.uploadedCount,
+        total: upload.fileCount,
+        label: pluralizeFiles(upload.fileCount),
+      })
+    : fileSummary;
+
+  const Icon = isError ? AlertCircle : isComplete ? CheckCircle2 : Upload;
+
+  return (
+    <div
+      className={cn(
+        'border-b px-3 py-2 transition-colors',
+        isError
+          ? 'border-red-500/20 bg-red-500/10 text-red-700 dark:text-red-300'
+          : isComplete
+          ? 'border-emerald-500/20 bg-emerald-500/10 text-emerald-700 dark:text-emerald-300'
+          : 'border-primary/20 bg-primary/10 text-foreground',
+      )}
+    >
+      <div className="flex min-h-[36px] items-center gap-2">
+        <div
+          className={cn(
+            'flex h-7 w-7 shrink-0 items-center justify-center rounded-md',
+            isError ? 'bg-red-500/15' : isComplete ? 'bg-emerald-500/15' : 'bg-primary/15',
+          )}
+        >
+          <Icon className={cn('h-3.5 w-3.5', isUploading && 'animate-pulse')} />
+        </div>
+        <div className="min-w-0 flex-1">
+          <div className="flex items-center justify-between gap-3">
+            <span className="truncate text-xs font-medium">{title}</span>
+            <span className="shrink-0 text-[11px] tabular-nums text-muted-foreground">
+              {isUploading ? `${progress}%` : isComplete ? t('common.done', 'Done') : t('common.failed', 'Failed')}
+            </span>
+          </div>
+          <div className="mt-1 truncate text-[11px] text-muted-foreground">{detail}</div>
+        </div>
+      </div>
+      <div className="mt-2 h-1.5 overflow-hidden rounded-full bg-background/80">
+        <div
+          className={cn(
+            'h-full rounded-full transition-[width] duration-200',
+            isError ? 'bg-red-500' : isComplete ? 'bg-emerald-500' : 'bg-primary',
+          )}
+          style={{ width: `${isError ? Math.max(progress, 8) : progress}%` }}
+        />
+      </div>
+    </div>
+  );
+}