Always set requester req

[jakub-id]

refactor a bit to ensure we're always reading from the right side

[Copilot]

Pull request overview

This PR refactors patron-request lookups and creation to ensure the code consistently reads/links requests from the correct “side” (borrowing vs lending), and to always populate requester_req_id for borrowing-side requests.

Changes:

• Ensure newly created borrowing patron requests always set RequesterReqID and do not persist SupplierSymbol.
• Add side-aware repository lookup (GetPatronRequestByIdAndSide) and restrict supplierSymbol/requesterReqId lookups to lending-side rows.
• Update message-handler, repo SQL, and related tests to use the new side-safe methods.

Reviewed changes

Copilot reviewed 9 out of 9 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
broker/test/patron_request/api/api-handler_test.go	Updates integration tests to reflect borrowing requests no longer returning supplierSymbol, and uses the explicit supplier symbol when querying lending-side actions.
broker/sqlc/pr_query.sql	Renames the supplierSymbol/requesterReqId query and adds side = 'lending' filtering to avoid returning borrowing-side rows.
broker/patron_request/service/message-handler_test.go	Updates mocks/expectations to use GetPatronRequestByIdAndSide and the lending-only supplierSymbol/requesterReqId lookup.
broker/patron_request/service/message-handler.go	Switches message-to-request resolution to side-aware lookups and lending-only supplierSymbol/requesterReqId lookup.
broker/patron_request/service/action_test.go	Extends the shared test mock repo to implement the new repo method(s) and renamed lookup.
broker/patron_request/db/prrepo.go	Adds GetPatronRequestByIdAndSide and renames/rewires the lending-only supplierSymbol/requesterReqId lookup.
broker/patron_request/api/api-handler_test.go	Extends unit tests to assert RequesterReqID is set and SupplierSymbol is unset for borrowing-side creation.
broker/patron_request/api/api-handler.go	Sets RequesterReqID on creation and forces borrowing-side SupplierSymbol to NULL.
broker/client/client_test.go	Updates the client-side test mock to satisfy the updated repo interface usage.