feat: Add image upload functionality with drag & drop, clipboard paste, and file picker (#46)

- Add drag & drop support for images with visual feedback
- Implement clipboard paste for images (Ctrl+V/Cmd+V)
- Add image upload button in chat interface
- Support multiple formats: PNG, JPG, JPEG, GIF, WebP, SVG
- Max 5 images per message, 5MB per image
- Add image preview with remove functionality
- Display images in chat message bubbles

Technical implementation:
- Frontend: Add react-dropzone for drag & drop
- Frontend: Create ImageAttachment component for previews
- Backend: Add multer for file upload handling
- Backend: Create /api/projects/:projectName/upload-images endpoint
- Backend: Convert images to base64 and save to temp files
- Claude CLI: Pass image paths as arguments
- Add automatic cleanup of temporary files
- Fix JWT auth to use correct token name
- Fix UI overlap with proper padding adjustments
- Remove non-essential console.logs for production

Security:
- Validate file types and sizes
- Sanitize filenames
- User-specific temp directories
- Proper JWT authentication

Infrastructure:
- Add .tmp/ to .gitignore
- Create comprehensive CHANGELOG.md
- Update package.json with new dependencies

Co-authored-by: viper151 <simosmik@gmail.com>

package.json

@@ -44,10 +44,12 @@
     "jsonwebtoken": "^9.0.2",
     "lucide-react": "^0.515.0",
     "mime-types": "^3.0.1",
+    "multer": "^2.0.1",
     "node-fetch": "^2.7.0",
     "node-pty": "^1.0.0",
     "react": "^18.2.0",
     "react-dom": "^18.2.0",
+    "react-dropzone": "^14.2.3",
     "react-markdown": "^10.1.0",
     "react-router-dom": "^6.8.1",
     "tailwind-merge": "^3.3.1",