fix: Add context.Background() to sqlite.New() calls in test files

Multiple test files were still using the old sqlite.New(path) signature
instead of the new sqlite.New(ctx, path) signature. This was causing
compilation failures in the test suite.

Fixed files:
- internal/importer/importer_test.go
- internal/importer/external_ref_test.go
- internal/importer/timestamp_test.go
- internal/rpc/limits_test.go
- internal/rpc/list_filters_test.go
- internal/rpc/rpc_test.go
- internal/rpc/status_test.go
- internal/syncbranch/syncbranch_test.go

internal/importer/importer_test.go

@@ -563,7 +563,7 @@ func TestImportIssues_Basic(t *testing.T) {
 	
 	// Create temp database
 	tmpDB := t.TempDir() + "/test.db"
-	store, err := sqlite.New(tmpDB)
+	store, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -609,7 +609,7 @@ func TestImportIssues_Update(t *testing.T) {
 	ctx := context.Background()
 	
 	tmpDB := t.TempDir() + "/test.db"
-	store, err := sqlite.New(tmpDB)
+	store, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -673,7 +673,7 @@ func TestImportIssues_DryRun(t *testing.T) {
 	ctx := context.Background()
 	
 	tmpDB := t.TempDir() + "/test.db"
-	store, err := sqlite.New(tmpDB)
+	store, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -709,7 +709,7 @@ func TestImportIssues_Dependencies(t *testing.T) {
 	ctx := context.Background()
 	
 	tmpDB := t.TempDir() + "/test.db"
-	store, err := sqlite.New(tmpDB)
+	store, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -762,7 +762,7 @@ func TestImportIssues_Labels(t *testing.T) {
 	ctx := context.Background()
 	
 	tmpDB := t.TempDir() + "/test.db"
-	store, err := sqlite.New(tmpDB)
+	store, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -806,7 +806,7 @@ func TestGetOrCreateStore_ExistingStore(t *testing.T) {
 	ctx := context.Background()
 	
 	tmpDB := t.TempDir() + "/test.db"
-	store, err := sqlite.New(tmpDB)
+	store, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -830,7 +830,7 @@ func TestGetOrCreateStore_NewStore(t *testing.T) {
 	tmpDB := t.TempDir() + "/test.db"
 	
 	// Create initial database
-	initStore, err := sqlite.New(tmpDB)
+	initStore, err := sqlite.New(context.Background(), tmpDB)
 	if err != nil {
 		t.Fatalf("Failed to create store: %v", err)
 	}
@@ -1003,7 +1003,7 @@ func TestConcurrentExternalRefImports(t *testing.T) {
 	t.Skip("TODO(bd-gpe7): Test hangs due to database deadlock - needs investigation")
 	
 	t.Run("sequential imports with same external_ref are detected as updates", func(t *testing.T) {
-		store, err := sqlite.New(":memory:")
+		store, err := sqlite.New(context.Background(), ":memory:")
 		if err != nil {
 			t.Fatalf("Failed to create store: %v", err)
 		}