test(repos): add SQL integration tests for 17 untested repo files

Add 148 integration tests exercising actual SQL against PostgreSQL for
all previously untested repository files. Includes 6 new fixture helpers
in testhelpers_db.go and CI PostgreSQL service configuration.

Discovered and documented existing RecordPurchase SQL bug (ambiguous
column reference in ON CONFLICT clause).

server/channelserver/repo_shop_test.go

@@ -0,0 +1,123 @@
+package channelserver
+
+import (
+	"testing"
+
+	"github.com/jmoiron/sqlx"
+)
+
+func setupShopRepo(t *testing.T) (*ShopRepository, *sqlx.DB, uint32) {
+	t.Helper()
+	db := SetupTestDB(t)
+	userID := CreateTestUser(t, db, "shop_test_user")
+	charID := CreateTestCharacter(t, db, userID, "ShopChar")
+	repo := NewShopRepository(db)
+	t.Cleanup(func() { TeardownTestDB(t, db) })
+	return repo, db, charID
+}
+
+func TestRepoShopGetShopItemsEmpty(t *testing.T) {
+	repo, _, charID := setupShopRepo(t)
+
+	items, err := repo.GetShopItems(1, 1, charID)
+	if err != nil {
+		t.Fatalf("GetShopItems failed: %v", err)
+	}
+	if len(items) != 0 {
+		t.Errorf("Expected 0 items, got: %d", len(items))
+	}
+}
+
+func TestRepoShopGetShopItems(t *testing.T) {
+	repo, db, charID := setupShopRepo(t)
+
+	// Insert shop items
+	if _, err := db.Exec(
+		`INSERT INTO shop_items (id, shop_type, shop_id, item_id, cost, quantity, min_hr, min_sr, min_gr, store_level, max_quantity, road_floors, road_fatalis)
+		VALUES (1, 1, 100, 500, 1000, 1, 0, 0, 0, 0, 99, 0, 0)`,
+	); err != nil {
+		t.Fatalf("Setup failed: %v", err)
+	}
+
+	items, err := repo.GetShopItems(1, 100, charID)
+	if err != nil {
+		t.Fatalf("GetShopItems failed: %v", err)
+	}
+	if len(items) != 1 {
+		t.Fatalf("Expected 1 item, got: %d", len(items))
+	}
+	if items[0].ItemID != 500 {
+		t.Errorf("Expected item_id=500, got: %d", items[0].ItemID)
+	}
+	if items[0].Cost != 1000 {
+		t.Errorf("Expected cost=1000, got: %d", items[0].Cost)
+	}
+	if items[0].UsedQuantity != 0 {
+		t.Errorf("Expected used_quantity=0, got: %d", items[0].UsedQuantity)
+	}
+}
+
+func TestRepoShopRecordPurchaseAmbiguousColumn(t *testing.T) {
+	repo, _, charID := setupShopRepo(t)
+
+	// RecordPurchase uses ON CONFLICT with unqualified "bought" column reference,
+	// which PostgreSQL rejects as ambiguous. This test documents the existing bug.
+	err := repo.RecordPurchase(charID, 1, 3)
+	if err == nil {
+		t.Fatal("Expected error from ambiguous column reference in RecordPurchase SQL, but got nil")
+	}
+}
+
+func TestRepoShopGetFpointItem(t *testing.T) {
+	repo, db, _ := setupShopRepo(t)
+
+	if _, err := db.Exec("INSERT INTO fpoint_items (id, item_type, item_id, quantity, fpoints, buyable) VALUES (1, 1, 100, 5, 200, true)"); err != nil {
+		t.Fatalf("Setup failed: %v", err)
+	}
+
+	quantity, fpoints, err := repo.GetFpointItem(1)
+	if err != nil {
+		t.Fatalf("GetFpointItem failed: %v", err)
+	}
+	if quantity != 5 {
+		t.Errorf("Expected quantity=5, got: %d", quantity)
+	}
+	if fpoints != 200 {
+		t.Errorf("Expected fpoints=200, got: %d", fpoints)
+	}
+}
+
+func TestRepoShopGetFpointExchangeList(t *testing.T) {
+	repo, db, _ := setupShopRepo(t)
+
+	if _, err := db.Exec("INSERT INTO fpoint_items (id, item_type, item_id, quantity, fpoints, buyable) VALUES (1, 1, 100, 5, 200, true)"); err != nil {
+		t.Fatalf("Setup failed: %v", err)
+	}
+	if _, err := db.Exec("INSERT INTO fpoint_items (id, item_type, item_id, quantity, fpoints, buyable) VALUES (2, 2, 200, 10, 500, false)"); err != nil {
+		t.Fatalf("Setup failed: %v", err)
+	}
+
+	exchanges, err := repo.GetFpointExchangeList()
+	if err != nil {
+		t.Fatalf("GetFpointExchangeList failed: %v", err)
+	}
+	if len(exchanges) != 2 {
+		t.Fatalf("Expected 2 exchange items, got: %d", len(exchanges))
+	}
+	// Ordered by buyable DESC, so buyable=true first
+	if !exchanges[0].Buyable {
+		t.Error("Expected first item to have buyable=true")
+	}
+}
+
+func TestRepoShopGetFpointExchangeListEmpty(t *testing.T) {
+	repo, _, _ := setupShopRepo(t)
+
+	exchanges, err := repo.GetFpointExchangeList()
+	if err != nil {
+		t.Fatalf("GetFpointExchangeList failed: %v", err)
+	}
+	if len(exchanges) != 0 {
+		t.Errorf("Expected 0 exchange items, got: %d", len(exchanges))
+	}
+}