[Reports] Add recent activity receipt search endpoint

[StuartFerguson]

Goal

Provide the backend API used by the mobile app's recent activity and receipt report screen.

Background

The mobile flow now has a dedicated recent activity page that:

• restricts the report to a single selected date
• pages results in chunks of 5
• sorts transactions by transaction date/time descending
• allows filtering by a free-text search term

At the moment the mobile app is using mocked data so the screen flow can be tested. This issue is to replace that mock with a real API-backed search endpoint.

Requirements

• Add a reporting endpoint for retrieving recent activity/receipt transactions for a single date.
• The endpoint must accept:
  • merchant context / merchant reporting id
  • report date
  • optional search text
  • page number
  • page size
• The endpoint must return:
  • the items for the requested page
  • total item count
  • page number
  • page size
  • total pages or enough metadata for the client to derive it
• Results must be ordered by transaction date/time descending.
• The date range must be restricted to a single date only.
• The result payload should support the fields already used by the mobile UI:
  • reference
  • transaction type
  • product
  • operator
  • status
  • amount
  • transaction date/time
  • receipt reference

Suggested response shape

• reportDate
• pageNumber
• pageSize
• totalCount
• items[]

Acceptance criteria

• A request for a given date returns only transactions from that date.
• Pagination works with page size 5.
• Search text filters results before paging is applied.
• Results are sorted descending by transaction date/time.
• The API response can be consumed by the mobile report screen without additional transformation beyond mapping DTOs.

Notes

• This is the search endpoint only. Receipt resend should be tracked in a separate issue.
• The mobile screen already expects the backend to be paged and date-restricted.

[StuartFerguson]

Adding a DTO suggestion for the search endpoint so implementation can stay consistent with the mobile flow:

Suggested request DTO

• GetRecentActivityReceiptReportRequest
  • MerchantReportingId or merchant context from auth
  • ReportDate
  • SearchText?
  • PageNumber
  • PageSize

Suggested response DTO

• GetRecentActivityReceiptReportResponse
  • ReportDate
  • PageNumber
  • PageSize
  • TotalCount
  • Items[]

Item DTO

• RecentActivityReceiptItemDto
  • Reference
  • TransactionType
  • Product
  • Operator
  • Status
  • Amount
  • TransactionDateTime
  • ReceiptReference

This keeps the contract explicit and matches the current mobile page bindings.