BackendFilter/Sort

[MatthewBarghout]

High-level motivation for making the changes
Added server-side pagination, sorting, and filtering to the /api/parties/ endpoint to improve performance and scalability as the database grows. Previously, all filtering and sorting happened client-side, which doesn't scale beyond a few hundred records.
Changes:
Core utilities (backend/src/core/query_utils.py):

Added reusable pagination, sorting, and filtering utilities for SQLAlchemy queries
Implemented PaginationParams, SortParam, FilterParam models with Pydantic validation
Created apply_query_params() to combine filters, sorting, and pagination with security whitelisting
Added get_total_count() to efficiently count filtered results before pagination

Party service (backend/src/modules/party/party_service.py):

Added get_parties_paginated() method with support for:

Optional pagination (page_number, page_size)
Sorting by party_datetime, location_id, contact_one_id, or id
Filtering by location_id and/or contact_one_id

Whitelisted allowed sort/filter fields for security

Party router (backend/src/modules/party/party_router.py):

Updated list_parties endpoint to accept query parameters for pagination, sorting, and filtering
All features are opt-in with sensible defaults (backward compatible)

Tests (backend/test/modules/party/test_party_list_features.py):

Added comprehensive test suite with 22 tests covering:

Pagination edge cases (empty DB, exact pages, remainders, beyond last page)
Sorting (ascending/descending by different fields)
Filtering (single and multiple filters)
Combined features (filter + sort + paginate together)

Bug fixes:

Fixed PartyTestUtils.next_dict() to avoid mutating the overrides dict (was causing test failures)
Fixed get_total_count() to properly count rows instead of columns

Closes #161

[github-actions]

Test Results Summary

302 tests  ±0   302 ✅ ±0   11s ⏱️ ±0s
  1 suites ±0     0 💤 ±0 
  1 files   ±0     0 ❌ ±0 

Results for commit b10ba3f. ± Comparison against base commit c972c7c.