test: pin scan_extractor_version at the start of ev-sensitive tests

The extractor/force-rescan tests assert manifest stamps against the
default version (1), but the setting lives in the SHARED dev DB — any
prior run (or a manual admin-UI bump) can leave it at 2, failing every
stamp assertion through no fault of the code. Each ev-sensitive test
now pins the setting to 1 at start and restores 1 on cleanup; proven
against a deliberately bumped setting (tests pass, row restored).

cmd/server/tests/extractor_version_test.go

@@ -74,6 +74,7 @@ func TestExtractorVersionReextract(t *testing.T) {
 
 	ctx := context.Background()
 	admin, _ := moveTestAdminID(t, setup)
+	pinExtractorVersionOne(t, setup)
 	libID, folder := createTypedTestLibrary(t, setup, fmt.Sprintf("Test EV Library %d", time.Now().UnixNano()), "ebooks")
 	t.Cleanup(func() { deleteLibraries(t, setup, libID) })
 
@@ -142,6 +143,7 @@ func TestExtractorVersionMultifile(t *testing.T) {
 	t.Cleanup(func() { _ = setup.Close() })
 
 	admin, _ := moveTestAdminID(t, setup)
+	pinExtractorVersionOne(t, setup)
 	libID, folder := audioTestLibrary(t, setup, fmt.Sprintf("Test EV Audio %d", time.Now().UnixNano()))
 	t.Cleanup(func() { deleteLibraries(t, setup, libID) })