Fix latest snapshot map ranking

CHANGELOG.md

@@ -20,6 +20,8 @@
   path, and retained every older snapshot.
 - Added compact Status UI, deterministic guardrail tests and readiness syntax
   coverage without changing migrations or enabling automatic refresh.
+- Fixed map theme ranking so a newer official observation always wins over an
+  older snapshot with a marginally larger feature count.
 
 ## Sprint 222 Official source edition probes (2026-07-16)
 

backend/tests/test_sprint223_governed_grb_refresh.py

@@ -248,3 +248,13 @@ def test_refresh_api_and_frontend_remain_explicit_only() -> None:
     assert "void probeCatalogs(" not in hook
     assert 'choices=("plan", "stage", "apply")' in operator
     assert "--confirm-plan-sha256" in operator
+
+
+def test_map_theme_ranking_prefers_newer_observation_over_feature_count() -> None:
+    root = Path(__file__).resolve().parents[2]
+    workspace = (root / "frontend" / "src" / "components" / "map" / "MapWorkspace.tsx").read_text(encoding="utf-8")
+    observed_sort = workspace.index("const observedAtDifference")
+    feature_tiebreaker = workspace.index("right.feature_count", observed_sort)
+    assert observed_sort < feature_tiebreaker
+    assert "new Date(right.observed_at ?? 0).getTime()" in workspace
+    assert "if (observedAtDifference !== 0) return observedAtDifference" in workspace

docs/CODEX_EXECUTION_LOG.md

@@ -9365,9 +9365,20 @@ Boundaries:
 Validation so far:
 - Backend compile and frontend typecheck passed.
 - Source-catalog plus governed-refresh focused suite passed: 20 tests.
-- Full `scripts/run_readiness_check.sh` passed: 779 backend tests, 110
+- Full `scripts/run_readiness_check.sh` passed: 780 backend tests, 110
   documented route contracts, one Alembic head, frontend typecheck/build and
   all packaged smoke checks.
+- Live Tower staging completed all 112 municipality/theme partitions for
+  official edition `2026-07-15`: 1,054,223 features, 1,250,873,313 artifact
+  bytes and staged plan SHA-256
+  `7a772b70771c223b14d16c097c917fb160883349df61e24a2730e8c9591d56fd`.
+- Checksum-confirmed apply created four new Datasets with exact PostGIS counts:
+  466,092 buildings, 84,513 roads, 88,330 water features and 415,288 parcels.
+  The four `2026-07-14` snapshots remain present; total project datasets moved
+  from 632 to 636 and source integrity remains zero-error.
+- Live browser validation exposed and fixed additive theme ranking where two
+  extra old water features could outweigh a newer observation date. Ranking is
+  now priority, observation date, import date, then feature-count tie-breaker.
 
 Next:
 - Run the full release gate, deploy to Tower, execute a live read-only plan and

frontend/src/components/map/MapWorkspace.tsx

@@ -279,7 +279,7 @@ function pickThemeDataset(
       && datasetCoversSelectedArea(dataset, selectedAreaId, regionalScope),
   )
   candidates.sort((left, right) => {
-    const score = (dataset: DatasetCreateResponse) =>
+    const priorityScore = (dataset: DatasetCreateResponse) =>
       (dataset.area_id && dataset.area_id === selectedAreaId ? 10_000_000 : 0) +
       (dataset.reference_layer_name && theme.tokens.includes(dataset.reference_layer_name.toLowerCase()) ? 1_000_000 : 0) +
       (dataset.source_name === 'grb' ? 100_000 : 0) +
@@ -292,10 +292,18 @@ function pickThemeDataset(
       (dataset.source_name === 'vmm_flood_hazard' ? 5_000_000 : 0) +
       (dataset.source_metadata?.['product_key'] === 'dtm_1m' ? 1_000_000 : 0) +
       (dataset.source_metadata?.['product_key'] === 'pluviaal_current_t100' ? 1_000_000 : 0) +
-      (dataset.dataset_role === 'reference' ? 10_000 : 0) +
-      (dataset.observed_at ? new Date(dataset.observed_at).getTime() / 100_000_000 : 0) +
-      (dataset.feature_count ?? dataset.vector_summary?.feature_count ?? 0)
-    return score(right) - score(left)
+      (dataset.dataset_role === 'reference' ? 10_000 : 0)
+    const priorityDifference = priorityScore(right) - priorityScore(left)
+    if (priorityDifference !== 0) return priorityDifference
+
+    const observedAtDifference = new Date(right.observed_at ?? 0).getTime() - new Date(left.observed_at ?? 0).getTime()
+    if (observedAtDifference !== 0) return observedAtDifference
+
+    const importedAtDifference = new Date(right.imported_at ?? 0).getTime() - new Date(left.imported_at ?? 0).getTime()
+    if (importedAtDifference !== 0) return importedAtDifference
+
+    return (right.feature_count ?? right.vector_summary?.feature_count ?? 0)
+      - (left.feature_count ?? left.vector_summary?.feature_count ?? 0)
   })
   return candidates[0] ?? null
 }