Implement General `/api/where/problem-reports` Search Endpoint

[AhmedAlian7]

Description

This issue implements the general search and list endpoint for problem reports (/api/where/problem-reports).
follow-up for #449

Context

Currently, there is no centralized way for transit operators to query reports across the entire system without knowing specific IDs.

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Proposed Changes

1. Database Layer (SQLC)

Re-introduce and expand the filtered queries in gtfsdb/query.sql. After updating the SQL, run make models to generate the Go code.

• Recent Reports: Implement GetRecentProblemReportsTrip and GetRecentProblemReportsStop with support for LIMIT and OFFSET.
• Filtering: * GetProblemReportsTripByDateRange / GetProblemReportsStopByDateRange
  • GetProblemReportsTripByCode / GetProblemReportsStopByCode

2. API Handler

Create a new handler file at internal/restapi/problem_reports_handler.go.

• Logic: Implement problemReportsHandler to parse the following query parameters:
  • startDate, endDate (ISO 8601)
  • code (Error/Category code)
  • offset, limit (Pagination)
• Aggregation: The handler should query both Trip and Stop reports, combine the results into a unified list, and sort them (typically by timestamp descending).

3. Routing

Register the new route in routes.go:

• Endpoint: GET /api/where/problem-reports
• Middleware: Ensure standard API key validation is applied. Note that this endpoint does not require a specific ID in the path.

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• I'm waiting for feat: Add API endpoints and database queries for retrieving problem reports by trip and stop. #449 merge to start working on it.

[richochetclementine1315]

hey! can i take up this issue?? @AhmedAlian7