Updates both the per-site report and the completion report for
result_migration_small_files_20260617 with a Phase 14 addendum that:
- Documents the 2 fixes (Issue 1: GUI subprocess crash; Issue 2:
xdist race in workspace fixture)
- References the follow-up track live_gui_test_fixes_20260618
- States the final test pass count: 11/11 tiers PASS clean
- Lists the remaining Gemini 503 skip markers as out of scope
- Confirms sub-track 2 is fully ready for merge with no documented
issues from this track
Sub-track 3 (result_migration_app_controller) is now unblocked.