Refactor: update S3 bucket structure for project files and task images

[Pradip-p]

PR Description:

This PR updates the MinIO S3 bucket path structure to better organize project files and task-related images:

• Project-level files such as dem.tif and map_screenshot.jpg are stored directly under the project directory.
• Task-specific images are now grouped under a dedicated images folder within each task directory.

The new structure is as follows:

projects/
└── project_id/
    ├── dem.tif
    ├── map_screenshot.jpg
    └── task_id/
        └── images/
            ├── image_1.jpg
            ├── image_2.jpg
            ├── image_3.jpg

screenshot