feat: implement bulk document management and fix upload pipeline

[riyapetle]

🚀 Overview
This PR introduces a highly requested Bulk Document Management feature, including a new Recycle Bin (Trash) system for safe recovery of deleted files. It also resolves critical backend issues related to background task ingestion, dependency conflicts, and development hot-reloading that were causing document uploads to hang and crash.

✨ Features & Enhancements

1. Bulk Document Operations (Frontend & Backend)
   Checkbox Selection: Added interactive checkboxes alongside documents in the DocumentSidebar, visible on hover.
   Bulk Action Bar: Implemented a slide-up Bulk Actions Bar that dynamically appears when documents are selected, allowing for multi-select deletion.
   New API Endpoints: Added /bulk-delete, /restore, and /permanent-delete POST endpoints to the FastAPI backend to handle arrays of document IDs securely.
2. Recycle Bin / Soft Deletes
   Active vs Trash Views: Built a toggle tab in the sidebar allowing users to seamlessly switch between "Active" documents and the "Recycle Bin".
   Safe Restoration: Added functionality to restore soft-deleted documents back to the Active view.
   Permanent Deletion: Added permanent deletion actions that safely remove the file from the disk and purge the associated vector embeddings from ChromaDB.
   🐛 Bug Fixes
3. Fixed "502 Bad Gateway" Upload Crashes
   Dependency Conflict: Resolved an underlying conflict between python-magic and python-magic-bin on Windows which caused the backend Python process to crash silently during MIME-type validation.
   Uvicorn Hot-Reload Loop: Updated the Makefile dev-backend command to use --reload-dir app instead of an ambiguous exclude glob. This prevents Uvicorn from infinitely restarting mid-upload when files are written to the ./data/uploads/ directory.
4. Fixed Infinite Upload Loading Times
   Bypassed Celery for Local Dev: Removed the blocking process_document.delay() Celery queue check during uploads. By routing directly to FastAPI's built-in BackgroundTasks, uploads now instantly return a 202 Accepted response while processing happens asynchronously.
5. Fixed 404 Routing Conflicts
   Route Precedence: Repositioned the GET /trash endpoint above the GET /{document_id} wildcard route in documents.py to prevent FastAPI from mistaking "trash" for a document ID.
   🧪 How to Test
   Launch both the Next.js frontend and the FastAPI backend.
   Upload multiple PDF files (notice how fast it uploads now without timing out).
   Hover over documents in the sidebar and check the boxes.
   Click Delete on the Bulk Actions bar to soft-delete them.
   Toggle to the Recycle Bin tab at the top of the sidebar.
   Select documents in the Trash and verify that you can Restore them or delete them Forever.

closes #422

[param20h]

CI checks chck them and update @riyapetle

[riyapetle]

Hey @param20h, I have fixed the TypeScript/linting errors and pushed the updates. Could you please approve the workflows to run the CI checks again?

[param20h]

solveee

[param20h]

ci chcks failing