Feature/deal repository crud

[Sakhila2001]

This PR implements full CRUD functionality for the Deal module, following the repository pattern and transactional data handling.

Features implemented:

• Deal creation, updating, listing, showing, and deletion
• Deal-level image handling via ImageService (store, replace, delete)
• Support for associating multiple products with a deal
• Soft-deleted pivot handling using SoftDeletePivotSyncService for product associations
• Active deal listing with eager-loaded relationships: products, brand, subcategory, variants, storages
• Clean transactional operations to ensure data consistency

Architecture & Design:

• Repository pattern for all deal operations

Dedicated helper services for:

• Image handling (ImageService)
• Product pivot sync with soft-delete support (SoftDeletePivotSyncService)
• Uses database transactions for store and update to maintain atomicity
• Soft deletes are respected throughout queries and pivot handling
• Eager loading of related models for efficient API responses

Testing done:

POST /api/admin/deals (store)
PUT /api/admin/deals/{deal} (update)
GET /api/admin/deals (index)
GET /api/admin/deals/{deal} (show)
DELETE /api/admin/deals/{deal} (destroy)

Verified:

• Deal creation, updates, and deletion work correctly
• Images are stored, replaced, and deleted as expected
• Products associated with deals are synced properly, respecting soft deletes
• Transactions rollback correctly on failure
• Eager-loaded relationships return correct data for products, brand, subcategory, variants, and storages