Tasks

• [x] Audit results, grouping and snapshot replacement; define compact-results scope.
• [x] Add regressions for grouping, bounded results and expiration.
• [x] Implement dashboard campground groups and independent pagination inside the upstream stay-date groups.
• [x] Expire past/out-of-range nights before matching saved scans.
• [x] Verify checks with UV_CONCURRENT_BUILDS=1 task test: 9 release, 569 backend and 336 frontend tests pass; all 76 visual snapshots match. The four standard grouped result views have zero changed pixels versus main. Preserve the local before/after gallery under frontend/tmp/compact-results-review/.
• [x] Update architecture docs and the global checklist.
• [x] Final review: prevent alerts from qualifying with expired/out-of-range nights; verify zero, one and two remaining nights in summary and direct modes.