fix(landscape): cast run status parameter so SetRunStatus type-checks in Postgres

The status parameter was used both as the assigned value (varchar column)
and in CASE comparisons against text literals, so Postgres deduced two
types for $2 and every run failed at SetRunStatus(running) with SQLSTATE
42P08; the failure also prevented marking the run failed, leaving it
queued. Cast every use to text.

Add TEST_DB_URL-gated repository tests (skipped without a database) that
exercise the landscape run/node SQL and the new dataset period/group
queries against a real Postgres, and document them in the README.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/repository/postgres/dataset_db_test.go

@@ -0,0 +1,115 @@
+package postgres
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"gis/internal/domain"
+
+	"github.com/google/uuid"
+)
+
+// TestDatasetRepository_GroupsPeriodsAndLatest exercises the Postgres-only
+// parts of the dataset/group repositories added with dataset periods: the
+// ::date casts on *string parameters, the date filter clause, and the
+// "freshest in group" ordering (end_date DESC NULLS LAST, created_at DESC).
+func TestDatasetRepository_GroupsPeriodsAndLatest(t *testing.T) {
+	pool := testPool(t)
+	ctx := context.Background()
+	groups := NewDatasetGroupRepository(pool)
+	datasets := NewDatasetRepository(pool)
+	categories := NewCategoryRepository(pool)
+
+	suffix := uuid.NewString()[:8]
+	cat, err := categories.Create(ctx, domain.Category{Code: "dbtest-" + suffix, Name: "db test"})
+	if err != nil {
+		t.Fatalf("create category: %v", err)
+	}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM categories WHERE id = $1`, cat.ID) })
+
+	group, err := groups.Create(ctx, domain.DatasetGroup{Code: "dbtest-group-" + suffix, Name: "db test group"})
+	if err != nil {
+		t.Fatalf("create group: %v", err)
+	}
+	t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM dataset_groups WHERE id = $1`, group.ID) })
+
+	s := func(v string) *string { return &v }
+	mk := func(name string, start, end *string) domain.Dataset {
+		d, err := datasets.Create(ctx, domain.Dataset{
+			CategoryID: cat.ID, DatasetGroupID: &group.ID, Name: name, Filename: name + ".tif",
+			StorageKey: "dbtest/" + suffix + "/" + name, FileType: domain.FileTypeRaster,
+			ContentType: "image/tiff", Status: domain.DatasetStatusReady,
+			StartDate: start, EndDate: end,
+		})
+		if err != nil {
+			t.Fatalf("create dataset %s: %v", name, err)
+		}
+		t.Cleanup(func() { _, _ = pool.Exec(ctx, `DELETE FROM datasets WHERE id = $1`, d.ID) })
+		time.Sleep(5 * time.Millisecond) // distinct created_at for the tie-break
+		return d
+	}
+
+	old := mk("old", s("2019-01-01"), s("2019-12-31"))
+	fresh := mk("fresh", s("2020-01-01"), s("2020-12-31"))
+	undated := mk("undated", nil, nil)
+
+	if old.StartDate == nil || *old.StartDate != "2019-01-01" || *old.EndDate != "2019-12-31" || old.DatasetGroupID == nil {
+		t.Fatalf("dates/group not round-tripped: %+v", old)
+	}
+
+	latest, err := datasets.LatestInGroup(ctx, group.ID, nil, nil)
+	if err != nil {
+		t.Fatalf("LatestInGroup: %v", err)
+	}
+	if latest.ID != fresh.ID {
+		t.Fatalf("latest = %s, want fresh %s (undated %s must sort last)", latest.Name, fresh.ID, undated.ID)
+	}
+	ft := domain.FileTypeVector
+	if _, err := datasets.LatestInGroup(ctx, group.ID, nil, &ft); !errors.Is(err, domain.ErrNotFound) {
+		t.Fatalf("no vector in group: err = %v, want ErrNotFound", err)
+	}
+
+	page, err := datasets.ListSummaries(ctx, domain.DatasetFilter{
+		DatasetGroupID: &group.ID, EndDateFrom: s("2020-01-01"), EndDateTo: s("2020-12-31"),
+	}, 10, 0)
+	if err != nil {
+		t.Fatalf("ListSummaries with date bounds: %v", err)
+	}
+	if len(page) != 1 || page[0].ID != fresh.ID {
+		t.Fatalf("date filter returned %+v, want only fresh", page)
+	}
+	n, err := datasets.Count(ctx, domain.DatasetFilter{DatasetGroupID: &group.ID, StartDateFrom: s("2019-06-01")})
+	if err != nil || n != 1 {
+		t.Fatalf("Count(start_date_from) = %d, %v; want 1", n, err)
+	}
+
+	updated, err := datasets.UpdateFields(ctx, undated.ID, domain.DatasetFields{
+		CategoryID: cat.ID, Name: "undated-now-dated", DatasetGroupID: &group.ID,
+		StartDate: s("2021-01-01"), EndDate: s("2021-12-31"),
+	})
+	if err != nil {
+		t.Fatalf("UpdateFields: %v", err)
+	}
+	if updated.EndDate == nil || *updated.EndDate != "2021-12-31" {
+		t.Fatalf("UpdateFields did not store the period: %+v", updated)
+	}
+	if _, err := datasets.UpdateFields(ctx, undated.ID, domain.DatasetFields{
+		CategoryID: cat.ID, Name: "bad", StartDate: s("2021-12-31"), EndDate: s("2021-01-01"),
+	}); !errors.Is(err, domain.ErrValidation) {
+		t.Fatalf("reversed period must hit the CHECK constraint: err = %v", err)
+	}
+
+	if err := groups.Delete(ctx, group.ID); !errors.Is(err, domain.ErrConflict) {
+		t.Fatalf("deleting a referenced group: err = %v, want ErrConflict", err)
+	}
+	g2, err := groups.SetSLD(ctx, group.ID, "k", "style.sld", "application/xml")
+	if err != nil || g2.SldStorageKey == nil || *g2.SldStorageKey != "k" {
+		t.Fatalf("SetSLD: %+v, %v", g2, err)
+	}
+	byCode, err := groups.GetByCode(ctx, group.Code)
+	if err != nil || byCode.ID != group.ID {
+		t.Fatalf("GetByCode: %+v, %v", byCode, err)
+	}
+}