Add unit test coverage across 16 source files (~96% → improved baseline)

[Copilot]

Extends unit test coverage for the PARTs WebAPI Django REST project, targeting files identified in docs/UNIT_TEST_PROGRESS.md with missing statement coverage.

New Test Files

• tests/admin/test_admin_phone_type_extra.py — admin/views.py PhoneType update-by-ID path
• tests/attendance/test_attendance_extra.py — attendance/util.py exempt-meeting and end_meeting loop; attendance/views.py save success
• tests/general/test_general_cloudinary_extra.py — general/cloudinary.py build_image_url(None) → return None
• tests/public/test_public_competition_extra.py — public/competition/views.py outer exception handler
• tests/scouting/test_scouting_easy_wins.py — scouting model __str__ methods, serializer field methods, util branches
• tests/sponsoring/test_sponsoring_extra.py — sponsoring/views.py invalid-data path; user/models.UserImage.__str__
• tests/form/test_form_views_extra.py — form/views.py send_email_notification for team-app/team-cntct form types
• tests/alerts/test_alerts_extra.py — alerts/util.py, alerts/views.py, alerts/util_alert_definitions.py stage/send branches
• tests/scouting/test_scouting_strategizing_extra2.py — strategizing/views.py and strategizing/util.py graph/dashboard branches
• tests/scouting/test_scouting_field_extra2.py — scouting/field/views.py direct view invocation (URL is commented out); scouting/field/util.py check-in red/blue positions
• tests/user/test_user_extra.py — user/util.py and user/views.py permission, image, superuser-field update paths
• tests/tba/test_tba_extra.py — tba/util.py sync and match-save branches
• tests/scouting/test_scouting_admin_views_extra2.py — scouting/admin/views.py schedule, mark-present, event-admin paths
• tests/scouting/test_scouting_admin_util_extra2.py — scouting/admin/util.py delete cascades, team linking, schedule save, field form image upload, user-season
• tests/form/test_form_util_extra2.py — form/util.py flow/question/aggregate save paths, send_email_notification

Notes

• ScoutingResponsesView is commented out of scouting/field/urls.py; tests invoke it directly via APIRequestFactory + view = ScoutingResponsesView.as_view().
• Several tests patch access_response / has_access with side_effect=lambda ...: fun() to isolate inner view logic.
• Some test failures remain from model field name mismatches and missing function references that need follow-up fixes before merging.