Enrich GoogleBatchPlatform instance template descriptions

Improve CLI help descriptions for new instance template options added from master:
- --head-job-template: Clarify usage with both short name and fully qualified reference formats
- --compute-job-template: Same clarification for compute jobs
- Add example format: projects/PROJECT_ID/global/instanceTemplates/TEMPLATE_NAME

These options were added to GoogleBatchPlatform from master branch merge.

Co-Authored-By: Claude Sonnet 4.5 <[email protected]>

Author: llewellyn-sl

src/main/java/io/seqera/tower/cli/commands/computeenvs/platforms/GoogleBatchPlatform.java

@@ -99,10 +99,10 @@ public static class AdvancedOptions {
         @Option(names = {"--service-account-email"}, description = "Google Cloud service account email for pipeline execution. Grants fine-grained IAM permissions to Nextflow jobs.")
         public String serviceAccountEmail;
 
-        @Option(names = {"--head-job-template"}, description = "The name or fully qualified reference of the instance template to use for the head job.")
+        @Option(names = {"--head-job-template"}, description = "Google Compute Engine instance template for the Nextflow head job. Specify either the template name (if in the same project) or the fully qualified reference (projects/PROJECT_ID/global/instanceTemplates/TEMPLATE_NAME).")
         public String headJobInstanceTemplate;
 
-        @Option(names = {"--compute-job-template"}, description = "The name or fully qualified reference of the instance template to use for the compute jobs.")
+        @Option(names = {"--compute-job-template"}, description = "Google Compute Engine instance template for pipeline compute jobs. Specify either the template name (if in the same project) or the fully qualified reference (projects/PROJECT_ID/global/instanceTemplates/TEMPLATE_NAME).")
         public String computeJobInstanceTemplate;
     }
 }