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_achievement_test.go

@@ -0,0 +1,133 @@
+package channelserver
+
+import (
+	"testing"
+
+	"github.com/jmoiron/sqlx"
+)
+
+func setupAchievementRepo(t *testing.T) (*AchievementRepository, *sqlx.DB, uint32) {
+	t.Helper()
+	db := SetupTestDB(t)
+	userID := CreateTestUser(t, db, "ach_test_user")
+	charID := CreateTestCharacter(t, db, userID, "AchChar")
+	repo := NewAchievementRepository(db)
+	t.Cleanup(func() { TeardownTestDB(t, db) })
+	return repo, db, charID
+}
+
+func TestRepoAchievementEnsureExists(t *testing.T) {
+	repo, db, charID := setupAchievementRepo(t)
+
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("EnsureExists failed: %v", err)
+	}
+
+	var count int
+	if err := db.QueryRow("SELECT COUNT(*) FROM achievements WHERE id=$1", charID).Scan(&count); err != nil {
+		t.Fatalf("Verification query failed: %v", err)
+	}
+	if count != 1 {
+		t.Errorf("Expected 1 row, got: %d", count)
+	}
+}
+
+func TestRepoAchievementEnsureExistsIdempotent(t *testing.T) {
+	repo, db, charID := setupAchievementRepo(t)
+
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("First EnsureExists failed: %v", err)
+	}
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("Second EnsureExists failed: %v", err)
+	}
+
+	var count int
+	if err := db.QueryRow("SELECT COUNT(*) FROM achievements WHERE id=$1", charID).Scan(&count); err != nil {
+		t.Fatalf("Verification query failed: %v", err)
+	}
+	if count != 1 {
+		t.Errorf("Expected 1 row after idempotent calls, got: %d", count)
+	}
+}
+
+func TestRepoAchievementGetAllScores(t *testing.T) {
+	repo, db, charID := setupAchievementRepo(t)
+
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("EnsureExists failed: %v", err)
+	}
+
+	// Set some scores directly
+	if _, err := db.Exec("UPDATE achievements SET ach0=10, ach5=42, ach32=99 WHERE id=$1", charID); err != nil {
+		t.Fatalf("Setup failed: %v", err)
+	}
+
+	scores, err := repo.GetAllScores(charID)
+	if err != nil {
+		t.Fatalf("GetAllScores failed: %v", err)
+	}
+	if scores[0] != 10 {
+		t.Errorf("Expected ach0=10, got: %d", scores[0])
+	}
+	if scores[5] != 42 {
+		t.Errorf("Expected ach5=42, got: %d", scores[5])
+	}
+	if scores[32] != 99 {
+		t.Errorf("Expected ach32=99, got: %d", scores[32])
+	}
+}
+
+func TestRepoAchievementGetAllScoresDefault(t *testing.T) {
+	repo, _, charID := setupAchievementRepo(t)
+
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("EnsureExists failed: %v", err)
+	}
+
+	scores, err := repo.GetAllScores(charID)
+	if err != nil {
+		t.Fatalf("GetAllScores failed: %v", err)
+	}
+	for i, s := range scores {
+		if s != 0 {
+			t.Errorf("Expected ach%d=0 by default, got: %d", i, s)
+		}
+	}
+}
+
+func TestRepoAchievementIncrementScore(t *testing.T) {
+	repo, db, charID := setupAchievementRepo(t)
+
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("EnsureExists failed: %v", err)
+	}
+
+	if err := repo.IncrementScore(charID, 5); err != nil {
+		t.Fatalf("First IncrementScore failed: %v", err)
+	}
+	if err := repo.IncrementScore(charID, 5); err != nil {
+		t.Fatalf("Second IncrementScore failed: %v", err)
+	}
+
+	var val int32
+	if err := db.QueryRow("SELECT ach5 FROM achievements WHERE id=$1", charID).Scan(&val); err != nil {
+		t.Fatalf("Verification query failed: %v", err)
+	}
+	if val != 2 {
+		t.Errorf("Expected ach5=2 after two increments, got: %d", val)
+	}
+}
+
+func TestRepoAchievementIncrementScoreOutOfRange(t *testing.T) {
+	repo, _, charID := setupAchievementRepo(t)
+
+	if err := repo.EnsureExists(charID); err != nil {
+		t.Fatalf("EnsureExists failed: %v", err)
+	}
+
+	err := repo.IncrementScore(charID, 33)
+	if err == nil {
+		t.Fatal("Expected error for achievementID=33, got nil")
+	}
+}