refactor(utils): one PgTextString for the four pgtype.Text unwrappers

handlers textToString, router textToString, router getText, and utils
normText were four copies of the same NULL-to-empty unwrap (99 call
sites). One exported utils.PgTextString replaces them all; the private
normText (comparison normalizer) stays but is now the odd one out.

Harness fix found on the way: setupTestServer built a full wiring
literal for route registration and then RETURNED a second, sparser
literal that never copied AnnotationService — setup.AnnotationService
was always nil on the struct every test receives. Nobody noticed until
cross_library_move_test became the first caller (it previously used
the now-retired plain CreateMediaHighlight query); it now exercises
the real SaveHighlight path through the wired service.

cmd/server/tests/test_helpers_test.go

@@ -710,18 +710,19 @@ func setupTestServer(t *testing.T) *TestServerSetup {
 
 	// Create TestServerSetup struct with all resources
 	setup := &TestServerSetup{
-		Server:          ts,
-		DB:              queries,
-		DBPool:          dbPool,
-		Config:          cfg,
-		ConnManager:     connManager,
-		QueueProcessor:  queueProcessor,
-		ProgressService: progressService,
-		CleanupCancel:   cleanupCancel,
-		QueueCtx:        queueCtx,
-		QueueCancel:     queueCancel,
-		Token:           adminToken,
-		RegularToken:    regularToken,
+		Server:            ts,
+		DB:                queries,
+		DBPool:            dbPool,
+		Config:            cfg,
+		ConnManager:       connManager,
+		QueueProcessor:    queueProcessor,
+		ProgressService:   progressService,
+		AnnotationService: annotationService,
+		CleanupCancel:     cleanupCancel,
+		QueueCtx:          queueCtx,
+		QueueCancel:       queueCancel,
+		Token:             adminToken,
+		RegularToken:      regularToken,
 	}
 
 	// Register cleanup function to run automatically when test completes