out of async for cost optimizaion

backend/service.yaml

@@ -8,8 +8,10 @@ spec:
   template:
     metadata:
       annotations:
-        autoscaling.knative.dev/minScale: "1"
+        autoscaling.knative.dev/minScale: "0"
         autoscaling.knative.dev/maxScale: "5"
+        run.googleapis.com/cpu-throttling: "true"
+        run.googleapis.com/startup-cpu-boost: "true"
     spec:
       timeoutSeconds: 300
       containers:
@@ -25,7 +27,7 @@ spec:
           value: "prod"
 
         - name: JAVA_TOOL_OPTIONS
-          value: "-Xms256m -Xmx512m -XX:+UseG1GC -XX:+ExitOnOutOfMemoryError"
+          value: "-Xms256m -Xmx512m -XX:+UseSerialGC -XX:+ExitOnOutOfMemoryError"
 
         - name: JDBC_URL
           valueFrom:

backend/src/main/java/com/thughari/jobtrackerpro/service/EmailService.java

@@ -4,7 +4,7 @@
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.mail.javamail.JavaMailSender;
 import org.springframework.mail.javamail.MimeMessageHelper;
-import org.springframework.scheduling.annotation.Async;
+
 import org.springframework.stereotype.Service;
 
 import jakarta.mail.MessagingException;
@@ -29,7 +29,6 @@ public class EmailService {
 	@Value("${email.sender_name}") 
 	private String fromName; 
 
-	@Async("taskExecutor")
 	public void sendResetEmail(String to, String token) {
 		try {
 			MimeMessage message = mailSender.createMimeMessage();
@@ -70,7 +69,6 @@ public void sendResetEmail(String to, String token) {
 		}
 	}
 
-	@Async("taskExecutor")
 	public void sendForwardingHelper(String to, String code, String link) {
 		try {
 			MimeMessage message = mailSender.createMimeMessage();
@@ -107,7 +105,6 @@ public void sendForwardingHelper(String to, String code, String link) {
 		}
 	}
 
-	@Async("taskExecutor")
     public void sendVerificationEmail(String to, String token) {
         try {
             MimeMessage message = mailSender.createMimeMessage();

backend/src/main/java/com/thughari/jobtrackerpro/service/GmailIntegrationService.java

@@ -23,7 +23,7 @@
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.cache.annotation.CacheEvict;
 import org.springframework.cache.annotation.Caching;
-import org.springframework.scheduling.annotation.Async;
+
 import org.springframework.stereotype.Service;
 import org.springframework.web.client.RestClient;
 
@@ -122,7 +122,6 @@ public void connectAndSetupPush(String authCode, String email) throws Exception
         log.info("User {} successfully connected Gmail. Watch set with label ID: {}", email, labelId);
     }
 
-    @Async("taskExecutor")
     public void initiateManualSync(String email) {
 
     	LocalDateTime now = LocalDateTime.now();
@@ -340,7 +339,6 @@ public void disconnectGmail(String email) {
         cleanupGoogleResourcesAsync(refreshToken, labelId);
     }
 
-    @Async("taskExecutor")
     protected void cleanupGoogleResourcesAsync(String refreshToken, String labelId) {
         try {
             String accessToken = getFreshAccessToken(refreshToken);

backend/src/main/java/com/thughari/jobtrackerpro/service/GmailWebhookService.java

@@ -14,7 +14,7 @@
 
 import lombok.extern.slf4j.Slf4j;
 import org.springframework.beans.factory.annotation.Value;
-import org.springframework.scheduling.annotation.Async;
+
 import org.springframework.stereotype.Service;
 
 import java.math.BigInteger;
@@ -49,7 +49,6 @@ public GmailWebhookService(GeminiService geminiService, JobService jobService, U
         this.cacheEvictService = cacheEvictService;
     }
 
-    @Async("taskExecutor")
     public void processHistorySync(String userEmail) {
         final String email = userEmail.toLowerCase();
 

backend/src/main/java/com/thughari/jobtrackerpro/service/IngestionService.java

@@ -5,7 +5,7 @@
 import com.thughari.jobtrackerpro.interfaces.GeminiService;
 import com.thughari.jobtrackerpro.repo.UserRepository;
 import lombok.extern.slf4j.Slf4j;
-import org.springframework.scheduling.annotation.Async;
+
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -23,7 +23,6 @@ public IngestionService(GeminiService geminiService, JobService jobService, User
         this.userRepository = userRepository;
     }
 
-    @Async("taskExecutor")
     @Transactional
     public void handleManualForward(String from, String subject, String body, String userEmail) {
         User user = userRepository.findByEmail(userEmail).orElse(null);

backend/src/main/java/com/thughari/jobtrackerpro/service/UserDeletionService.java

@@ -15,7 +15,7 @@
 import org.springframework.cache.CacheManager;
 import org.springframework.cache.annotation.CacheEvict;
 import org.springframework.cache.annotation.Caching;
-import org.springframework.scheduling.annotation.Async;
+
 import org.springframework.stereotype.Service;
 import org.springframework.transaction.annotation.Transactional;
 
@@ -115,7 +115,6 @@ public DeletionWarning checkPendingDeletion(String email) {
      * Ensures complete cleanup across all systems
      */
     @Transactional
-    @Async
     public void deleteUserCompletely(String email) {
 
         User user = userRepository.findByEmail(email)