Enhancement: Media Bank & Asynchronous product saving for future releases

Is your feature request related to a problem? Please describe.

Even in Bagisto v2.5.0‑beta1, which brings S3 / Cloudflare R2 cloud storage, refactored search engine and Laravel queue support, two major pain‑points still exist for store administrators:

1. No centralized Media / Image Bank: There is no admin menu to manage uploaded assets. Merchants must repeatedly upload identical images for multiple products. It creates duplicated files, wastes storage and reduces work efficiency. Existing uploaded images cannot be directly reused on product forms.
2. Synchronous product saving causes timeouts: When saving heavy configurable products with dozens of variants and multiple images, image resizing, variant generation and search‑index rebuild run synchronously inside HTTP request. This often triggers 504 gateway timeout errors. Administrators need to wait a long time for page responses.

Describe the solution you'd like

1. Media Bank (Image Bank)

• Add a dedicated Media Bank admin menu for asset management: upload, preview, search, categorize, rename and delete images.
• Fully compatible with existing storage drivers shipped in v2.5: local disk, Amazon S3, Cloudflare R2.
• Extend product image upload component: open a modal picker to select existing assets from Media Bank besides local upload. One image can be referenced by multiple products without file duplication.
• Re‑use the built‑in Illuminate\Image processing logic introduced in v2.5.

1. Asynchronous product submit

• Offload heavy operations (image processing, variant generation, search index building) to Laravel background queue jobs. Return immediate HTTP response after submitting product form.
• Add an admin panel to view product‑related job status: pending / success / failed, expose error logs for failed tasks.
• Keep traditional synchronous saving as fallback for simple products.
• Reuse Bagisto’s existing Supervisor‑based queue system.

This feature does not require large‑scale underlying refactoring, since v2.5‑beta1 has already implemented storage abstraction, queue infrastructure and new image processing layer. It mainly requires admin UI and business logic implementation.

Describe alternatives you've considered

1. Manually manage files directly on server or object‑storage console: no linkage with Bagisto catalog system, error‑prone for non‑technical operators.
2. Custom module development: implement media library and async saving manually. But custom code brings high maintenance cost during future Bagisto version upgrades.

Additional context

Expectation for future versions: Hope this enhancement can be evaluated for future releases such as v2.6.

v2.5 stable is focused on bug fixes for beta, so new major features are unlikely to land in v2.5.x series. These two functions will bring huge improvements for cross‑border merchants who maintain large catalogs and complex configurable products.