Upload: Progress indicator for uploads

[Ayush8923]

Is your feature request related to a problem?
Large document uploads only show a generic loading state in the UI. Users lack visibility into upload progress and estimated time remaining, which can lead to frustration.

Describe the solution you'd like

• Add an uploadWithProgress helper in app/lib/apiClient.ts using XMLHttpRequest for upload.onprogress
• Track uploadProgress percentage state in app/(main)/document/page.tsx
• Display a progress bar in UploadDocumentModal when isUploading is true
• No backend changes required - XHR handles bytes sent from browser to server

Original issue

Describe the current behavior
When uploading large documents, the UI only shows a generic loading state (isUploading). Users have no visibility into upload progress or estimated time remaining.

Describe the enhancement you'd like

• Add an uploadWithProgress helper in app/lib/apiClient.ts using XMLHttpRequest (which supports upload.onprogress, unlike fetch)
• Track uploadProgress percentage state in app/(main)/document/page.tsx
• Display a progress bar in UploadDocumentModal when isUploading is true
• No backend changes required for now - XHR tracks bytes sent from browser to server

[Ayush8923]

As per the discussion with team, also need to add a document upload limit of up to 25 MB.